Sense line structures in capacitive sense nand memory

ABSTRACT

Arrays of memory cells might include a data line, a source, a plurality of pass gates connected in series between the data line and the source, a plurality of unit column structures each having a respective plurality of series-connected non-volatile memory cells connected in series with a respective plurality of series-connected field-effect transistors, wherein a channel of each non-volatile memory cell of its respective plurality of series-connected non-volatile memory cells and a channel of each field-effect transistor of its respective plurality of series-connected field-effect transistors are selectively connected to one another, and a plurality of backside gate lines each connected to the second control gate of a respective pass gate of the plurality of pass gates, wherein, for each unit column structure of the plurality of unit column structures, the channel of a particular field-effect transistor of its respective plurality of field-effect transistors is capacitively coupled to the first channel of a respective pass gate of the plurality of pass gates.

RELATED APPLICATIONS

This application is related to U.S. Patent Application Serial No. [Atty.Dkt. No. M3401.195.101] titled “Capacitive Sense NAND Memory” and filedeven date herewith, U.S. Patent Application Serial No. [Atty. Dkt. No.M3401.212.101] titled “Memory Array Structures for Capacitive Sense NANDMemory” and filed even date herewith, and U.S. Patent Application SerialNo. [Atty. Dkt. No. M3401.214.101] titled “Access Operations inCapacitive Sense NAND Memory” and filed even date herewith, each suchapplication being commonly assigned and incorporated by reference in itsentirety, and each such application sharing common disclosure.

TECHNICAL FIELD

The present disclosure relates generally to integrated circuits, and, inparticular, in one or more embodiments, the present disclosure relatesto apparatus including strings of series-connected memory cells, and tomethods of their formation and operation.

BACKGROUND

Integrated circuit devices traverse a broad range of electronic devices.One particular type include memory devices, oftentimes referred tosimply as memory. Memory devices are typically provided as internal,semiconductor, integrated circuit devices in computers or otherelectronic devices. There are many different types of memory includingrandom-access memory (RAM), read only memory (ROM), dynamic randomaccess memory (DRAM), synchronous dynamic random access memory (SDRAM),and flash memory.

Flash memory has developed into a popular source of non-volatile memoryfor a wide range of electronic applications. Flash memory typically usea one-transistor memory cell that allows for high memory densities, highreliability, and low power consumption. Changes in threshold voltage(Vt) of the memory cells, through programming (which is often referredto as writing) of charge storage structures (e.g., floating gates orcharge traps) or other physical phenomena (e.g., phase change orpolarization), determine the data state (e.g., data value) of eachmemory cell. Common uses for flash memory and other non-volatile memoryinclude personal computers, personal digital assistants (PDAs), digitalcameras, digital media players, digital recorders, games, appliances,vehicles, wireless devices, mobile telephones, and removable memorymodules, and the uses for non-volatile memory continue to expand.

A NAND flash memory is a common type of flash memory device, so calledfor the logical form in which the basic memory cell configuration isarranged. Typically, the array of memory cells for NAND flash memory isarranged such that the control gate of each memory cell of a row of thearray is connected together to form an access line, such as a word line.Columns of the array include strings (often termed NAND strings) ofmemory cells connected together in series between a pair of selectgates, e.g., a source select transistor and a drain select transistor.Each source select transistor might be connected to a source, while eachdrain select transistor might be connected to a data line, such ascolumn bit line. Variations using more than one select gate between astring of memory cells and the source, and/or between the string ofmemory cells and the data line, are known.

The desire for higher levels of memory storage density has led to longerstrings of series-connected memory cells in NAND memory. However, commonindustrial techniques may present challenges in the successfulfabrication of such strings of series-connected memory cells, e.g.,placing a practical limit on the number of memory cells containedtherein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of a memory in communication with aprocessor as part of an electronic system, according to an embodiment.

FIGS. 2A-2B are schematics of portions of an array of memory cells ascould be used in a memory of the type described with reference to FIG.1, according to embodiments.

FIG. 2C is a perspective conceptualization of a portion of an array ofmemory cells over peripheral circuitry as could be used in a memory ofthe type described with reference to FIG. 1, according to a furtherembodiment.

FIGS. 3A-3E are conceptual depictions of portions of a block of memorycells using array structures such as depicted in FIG. 2A anddemonstrating layouts of backside gate lines, sense select lines, senselines, common source, and lower data lines, according to embodiments.

FIGS. 3F-3G are conceptual depictions of a portion of a block of memorycells using an array structure such as depicted in FIG. 2B anddemonstrating a layout of backside gate lines, sense select lines, senselines, common source, and lower data lines, according to additionalembodiments.

FIG. 4A is a conceptual depiction of a portion of a block of memorycells using an array structure such as depicted in FIGS. 3A and 3B, anddemonstrating a layout of upper data line connectivity, according to anembodiment.

FIG. 4B is a conceptual depiction of a portion of a block of memorycells using an array structure such as depicted in FIGS. 3C and 3D, anddemonstrating a layout of upper data line connectivity, according toanother embodiment.

FIG. 4C is a conceptual depiction of a portion of a block of memorycells using an array structure such as depicted in FIGS. 3C and 3E, anddemonstrating a layout of upper data line connectivity, according to afurther embodiment.

FIG. 4D is a conceptual depiction of a portion of a block of memorycells using an array structure such as depicted in FIGS. 3F and 3G, anddemonstrating a layout of upper data line connectivity, according to astill further embodiment.

FIGS. 5A-5N depict an integrated circuit structure during various stagesof fabrication in accordance with embodiments.

FIGS. 6A-6F depict an integrated circuit structure during various stagesof fabrication in accordance with additional embodiments.

FIGS. 7A-7J depict orthogonal views of various structures for senselines in accordance with embodiments.

FIGS. 8A-8C depict an integrated circuit structure during various stagesof fabrication in accordance with an embodiment.

FIGS. 9A-9E depict an integrated circuit structure during various stagesof fabrication in accordance with another embodiment.

FIGS. 10A-10B depict integrated circuit structures in accordance withfurther embodiments.

FIG. 11 is a timing diagram of a method of operating a memory inaccordance with an embodiment.

FIG. 12 is a timing diagram of a method of operating a memory inaccordance with a different embodiment.

FIG. 13 is a timing diagram of a method of operating a memory inaccordance with another embodiment.

FIG. 14 is a timing diagram of a method of operating a memory inaccordance with a further embodiment.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings that form a part hereof, and in which is shown, byway of illustration, specific embodiments. In the drawings, likereference numerals describe substantially similar components throughoutthe several views. Other embodiments might be utilized and structural,logical and electrical changes might be made without departing from thescope of the present disclosure. The following detailed description is,therefore, not to be taken in a limiting sense.

The term “semiconductor” used herein can refer to, for example, a layerof material, a wafer, or a substrate, and includes any basesemiconductor structure. “Semiconductor” is to be understood asincluding silicon-on-sapphire (SOS) technology, silicon-on-insulator(SOI) technology, thin film transistor (TFT) technology, doped andundoped semiconductors, epitaxial layers of a silicon supported by abase semiconductor structure, as well as other semiconductor structureswell known to one skilled in the art. Furthermore, when reference ismade to a semiconductor in the following description, previous processsteps might have been utilized to form regions/junctions in the basesemiconductor structure, and the term semiconductor can include theunderlying layers containing such regions/junctions.

The term “conductive” as used herein, as well as its various relatedforms, e.g., conduct, conductively, conducting, conduction,conductivity, etc., refers to electrically conductive unless otherwiseapparent from the context. Similarly, the term “connecting” as usedherein, as well as its various related forms, e.g., connect, connected,connection, etc., refers to electrically connecting unless otherwiseapparent from the context.

It is recognized herein that even where values might be intended to beequal, variabilities and accuracies of industrial processing andoperation might lead to differences from their intended values. Thesevariabilities and accuracies will generally be dependent upon thetechnology utilized in fabrication and operation of the integratedcircuit device. As such, if values are intended to be equal, thosevalues are deemed to be equal regardless of their resulting values.

FIG. 1 is a simplified block diagram of a first apparatus, in the formof a memory (e.g., memory device) 100, in communication with a secondapparatus, in the form of a processor 130, as part of a third apparatus,in the form of an electronic system, according to an embodiment. Someexamples of electronic systems include personal computers, personaldigital assistants (PDAs), digital cameras, digital media players,digital recorders, games, appliances, vehicles, wireless devices, mobiletelephones and the like. The processor 130, e.g., a controller externalto the memory device 100, might be a memory controller or other externalhost device.

Memory device 100 includes an array of memory cells 104 logicallyarranged in rows and columns. Memory cells of a logical row aretypically connected to the same access line (commonly referred to as aword line) while memory cells of a logical column are typicallyselectively connected to the same data line (commonly referred to as abit line). A single access line might be associated with more than onelogical row of memory cells and a single data line might be associatedwith more than one logical column. Memory cells (not shown in FIG. 1) ofat least a portion of array of memory cells 104 are capable of beingprogrammed to one of at least two target data states. The array ofmemory cells 104 includes an array structure in accordance with one ormore embodiments described herein.

A row decode circuitry 108 and a column decode circuitry 110 areprovided to decode address signals. Address signals are received anddecoded to access the array of memory cells 104. Memory device 100 alsoincludes input/output (I/O) control circuitry 112 to manage input ofcommands, addresses and data to the memory device 100 as well as outputof data and status information from the memory device 100. An addressregister 114 is in communication with I/O control circuitry 112 and rowdecode circuitry 108 and column decode circuitry 110 to latch theaddress signals prior to decoding. A command register 124 is incommunication with I/O control circuitry 112 and control logic 116 tolatch incoming commands.

A controller (e.g., the control logic 116 internal to the memory device100) controls access to the array of memory cells 104 in response to thecommands and generates status information for the external processor130, i.e., control logic 116 is configured to perform access operations(e.g., sensing operations [which might include read operations andverify operations], programming operations and/or erase operations) onthe array of memory cells 104. The control logic 116 is in communicationwith row decode circuitry 108 and column decode circuitry 110 to controlthe row decode circuitry 108 and column decode circuitry 110 in responseto the addresses. The control logic 116 might include instructionregisters 128 which might represent computer-usable memory for storingcomputer-readable instructions. For some embodiments, the instructionregisters 128 might represent firmware. Alternatively, the instructionregisters 128 might represent a grouping of memory cells, e.g., reservedblock(s) of memory cells, of the array of memory cells 104.

Control logic 116 is also in communication with a cache register 118.Cache register 118 latches data, either incoming or outgoing, asdirected by control logic 116 to temporarily store data while the arrayof memory cells 104 is busy writing or reading, respectively, otherdata. During a programming operation (e.g., write operation), data mightbe passed from the cache register 118 to the data register 120 fortransfer to the array of memory cells 104; then new data might belatched in the cache register 118 from the I/O control circuitry 112.During a read operation, data might be passed from the cache register118 to the I/O control circuitry 112 for output to the externalprocessor 130; then new data might be passed from the data register 120to the cache register 118. The cache register 118 and/or the dataregister 120 might form (e.g., might form a portion of) a page buffer ofthe memory device 100. A page buffer might further include sensingdevices (not shown in FIG. 1) to sense a data state of a memory cell ofthe array of memory cells 104, e.g., by sensing a state of a data lineconnected to that memory cell. A status register 122 might be incommunication with I/O control circuitry 112 and control logic 116 tolatch the status information for output to the processor 130.

Memory device 100 is depicted to receive control signals at controllogic 116 from processor 130 over a control link 132. The controlsignals might include a chip enable CE #, a command latch enable CLE, anaddress latch enable ALE, a write enable WE #, a read enable RE #, and awrite protect WP #. Additional or alternative control signals (notshown) might be further received over control link 132 depending uponthe nature of the memory device 100. Memory device 100 receives commandsignals (which represent commands), address signals (which representaddresses), and data signals (which represent data) from processor 130over a multiplexed input/output (I/O) bus 134 and outputs data toprocessor 130 over I/O bus 134.

For example, the commands might be received over input/output (I/O) pins[7:0] of I/O bus 134 at I/O control circuitry 112 and might then bewritten into command register 124. The addresses might be received overinput/output (I/O) pins [7:0] of I/O bus 134 at I/O control circuitry112 and might then be written into address register 114. The data mightbe received over input/output (I/O) pins [7:0] for an 8-bit device orinput/output (I/O) pins [15:0] for a 16-bit device at I/O controlcircuitry 112 and then might be written into cache register 118. Thedata might be subsequently written into data register 120 forprogramming the array of memory cells 104. For another embodiment, cacheregister 118 might be omitted, and the data might be written directlyinto data register 120. Data might also be output over input/output(I/O) pins [7:0] for an 8-bit device or input/output (I/O) pins [15:0]for a 16-bit device. Although reference might be made to I/O pins, theymight include any conductive node providing for electrical connection tothe memory device 100 by an external device (e.g., processor 130), suchas conductive pads or conductive bumps as are commonly used.

It will be appreciated by those skilled in the art that additionalcircuitry and signals can be provided, and that the memory device 100 ofFIG. 1 has been simplified. It should be recognized that thefunctionality of the various block components described with referenceto FIG. 1 might not necessarily be segregated to distinct components orcomponent portions of an integrated circuit device. For example, asingle component or component portion of an integrated circuit devicecould be adapted to perform the functionality of more than one blockcomponent of FIG. 1. Alternatively, one or more components or componentportions of an integrated circuit device could be combined to performthe functionality of a single block component of FIG. 1. Additionally,while specific I/O pins are described in accordance with popularconventions for receipt and output of the various signals, it is notedthat other combinations or numbers of I/O pins (or other I/O nodestructures) might be used in the various embodiments.

FIG. 2A is a schematic of a portion of an array of memory cells 200A,such as a NAND memory array, as could be used in a memory of the typedescribed with reference to FIG. 1, e.g., as a portion of array ofmemory cells 104. Memory array 200A includes access lines, such as wordlines 202 ₀ to 202 _(N), and data lines, such as first, or upper, datalines (e.g., upper bit lines) 204 ₀ to 204 _(M) and second, or lower,data line (e.g., lower bit line) 254. The word lines 202 might beconnected to global access lines (e.g., global word lines), not shown inFIG. 2A, in a many-to-one relationship. For some embodiments, memoryarray 200A might be formed over a semiconductor that, for example, mightbe conductively doped to have a conductivity type, such as a p-typeconductivity, e.g., to form a p-well, or an n-type conductivity, e.g.,to form an n-well. In addition, the memory array 200A might be formedover other circuitry, e.g., peripheral circuitry under the memory array200A and used for controlling access to the memory cells of the memoryarray 200A. It is noted that directional descriptors used herein, e.g.,lower, upper, over, under, etc., are relative and do not require anyparticular orientation in physical space.

Memory array 200A might be arranged in rows (each corresponding to aword line 202 and a lower data line 254) and columns (each correspondingto a upper data line 204). Each column might include a string ofseries-connected memory cells (e.g., non-volatile memory cells), such asone of NAND strings 206 ₀ to 206 _(M). The memory cells 208 mightrepresent non-volatile memory cells for storage of data. The memorycells 208 of each NAND string 206 might be connected in series between aselect gate 210 (e.g., a field-effect transistor), such as one of theselect gates 210 ₀ to 210 _(M) (e.g., lower select gates), and a selectgate 212 (e.g., a field-effect transistor), such as one of the selectgates 212 ₀ to 212 _(M) (e.g., upper select gates). Lower select gates210 ₀ to 210 _(M) might be commonly connected to a select line 214, suchas a lower select line LSG, and upper select gates 212 ₀ to 212 _(M)might be commonly connected to a select line 215, such as an upperselect line USG. Although depicted as traditional field-effecttransistors, the lower select gates 210 and upper select gates 212 mightutilize a structure similar to (e.g., the same as) the memory cells 208.The lower select gates 210 and upper select gates 212 might eachrepresent a plurality of select gates connected in series, with eachselect gate in series configured to receive a same or independentcontrol signal.

Typical construction of memory cells 208 includes a data-storagestructure 234 (e.g., a floating gate, charge trap, or other structureconfigured to store charge) that can determine a data state of thememory cell (e.g., through changes in threshold voltage), and a controlgate 236, as shown in FIG. 2A. The data-storage structure 234 mightinclude both conductive and dielectric structures while the control gate236 is generally formed of one or more conductive materials. In somecases, memory cells 208 might further have a defined source/drain (e.g.,source) 230 and a defined source/drain (e.g., drain) 232. Memory cells208 have their control gates 236 connected to (and in some cases form) aword line 202.

The lower select gates 210 of each NAND string 206 might be connected inseries between its memory cells 208 and a respective capacitance 226,e.g., one of capacitances 226 ₀ to 226 _(M). Each lower select gate 210might be connected (e.g., directly connected) to its respectivecapacitance 226. Each lower select gate 210 might further be connected(e.g., directly connected) to the memory cell 208 ₀ of its correspondingNAND string 206. For example, the lower select gate 210 ₀ might beconnected to the capacitance 226 ₀, and the lower select gate 210 ₀might be connected to memory cell 208 ₀ of the corresponding NAND string206 ₀. Therefore, each lower select gate 210 might be configured toselectively connect a corresponding NAND string 206 to a respectivecapacitance 226. A control gate of each lower select gate 210 might beconnected to select line 214.

The upper select gates 212 of each NAND string 206 might be connected inseries between its memory cells 208 and a GIDL (gate-induced drainleakage) generator gate 220 (e.g., a field-effect transistor), such asone of the GIDL generator (GG) gates 220 ₀ to 220 _(M). The GG gates 220₀ to 220 _(M) might be connected (e.g., directly connected) to theirrespective upper data lines 204 ₀ to 204 _(M), and selectively connectedto their respective NAND strings 206 ₀ to 206 _(M), e.g., throughrespective upper select gates 212 ₀ to 212 _(M).

GG gates 220 ₀ to 220 _(M) might be commonly connected to a control line224, such as a GG control line. Although depicted as traditionalfield-effect transistors, the GG gates 220 may utilize a structuresimilar to (e.g., the same as) the memory cells 208. The GG gates 220might represent a plurality of GG gates connected in series, with eachGG gate in series configured to receive a same or independent controlsignal. In general, the GG gates 220 may have threshold voltagesdifferent than (e.g., lower than) the threshold voltages of the upperselect gates 212. Threshold voltages of the GG gates 220 may be of anopposite polarity than, and/or may be lower than, threshold voltages ofthe upper select gates 212. For example, the upper select gates 212might have positive threshold voltages (e.g., 2V to 4V), while the GGgates 220 might have negative threshold voltages (e.g., −1V to −4V). TheGG gates 220 might be provided to assist in the generation of GIDLcurrent into a channel region of their corresponding NAND string 206during a read operation or an erase operation, for example.

Each GG gate 220 might be connected (e.g., directly connected) to theupper data line 204 for the corresponding NAND string 206. For example,the GG gate 220 ₀ might be connected to the upper data line 204 ₀ forits corresponding NAND string 2060. Each GG gate 220 might be connected(e.g., directly connected) to the upper select gate 212 of itscorresponding NAND string 206. For example, GG gate 220 ₀ might beconnected to the upper select gate 212 ₀ of the corresponding NANDstring 2060. Each upper select gate 212 might further be connected(e.g., directly connected) to the memory cell 208 _(N) of itscorresponding NAND string 206. For example, the upper select gate 212 ₀might be connected to memory cell 208 _(N) of the corresponding NANDstring 2060. Therefore, in cooperation, each upper select gate 212 andGG gate 220 for a corresponding NAND string 206 might be configured toselectively connect that NAND string 206 to the corresponding upper dataline 204. A control gate of each GG gate 220 might be connected tocontrol line 224. A control gate of each upper select gate 212 might beconnected to select line 215.

One electrode of each capacitance 226 might be connected to control line228, e.g., control line CAP. A different electrode of each capacitance226 might be capacitively coupled to a respective pass gate 238, e.g.,pass gates 238 ₀ to 238 _(M). For example, the capacitance 226 ₀ mightbe capacitively coupled to, or electrically connected to, a firstcontrol gate 240 of the pass gate 238 ₀, and thus capacitively coupledto a channel of the pass gate 2380. A second control gate 242 of eachpass gate 238 might be connected (e.g., directly connected) to arespective backside gate line 244, e.g., backside gate lines 244 ₀ to244 _(M). For example, the second control gate 242 of pass gate 238 ₀might be connected to the backside gate line 244 ₀. The pass gates 238might be connected in series between the a source 216 (e.g., commonsource SRC) as one voltage node, and the lower data line 254 as anothervoltage node, and their resulting current path might be referred to as asense line 258. One pass gate 238, e.g., pass gate 238 ₀, might beselectively connected to the lower data line 254 through a first senseselect gate (e.g., field-effect transistor) 246. A control gate of thefirst sense select gate 246 might be connected to a first sense selectline 248. Another pass gate 238, e.g., pass gate 238 _(M), might beselectively connected to the common source 216 through a second senseselect gate (e.g., field-effect transistor) 250. A control gate of thesecond sense select gate 250 might be connected to a second sense selectline 252.

Pass gates 238 might be deemed to be two field-effect transistorsconnected in parallel that are responsive to two control gates, e.g.,the first control gate 240 and the second control gate 242. The twofield-effect transistors of a pass gate 238 might have discretechannels, e.g., one channel capacitively coupled to the first controlgate 240 and another channel capacitively coupled to the second controlgate 242. Alternatively, a first channel of a pass gate 238 capacitivelycoupled to the first control gate 240 and a second channel of the passgate 238 capacitively coupled to the second control gate 242 might be asame channel of that pass gate 238.

A sensing device 268 might be connected to the lower data line 254 foruse in sensing a data state of a memory cell 208, e.g., by sensing astate of the lower data line 254. For example, the sensing device 268might be used to detect whether the lower data line 254 is experiencingcurrent flow, or experiencing a change in voltage level, to determinewhether a unit column structure 256 containing a memory cell 208selected for sensing stores a sufficient level of electrical charge toactivate the first control gate 240 of its corresponding pass gate 238while the second control gate 242 of that pass gate 238 is deactivated.During such sensing, the remaining pass gates in the sense line 258might have their second control gates 242 activated. In this manner,electrically connecting the lower data line to the common source 216through the sense line 258 could indicate that the selected memory cellhas one data state, while electrically isolating the lower data linefrom the common source 216 could indicate that the selected memory cellhas a different data state.

Although each capacitance 226 is depicted as a single capacitance foreach NAND string 206, each capacitance 226 might represent a number offield-effect transistors connected in series, and each such transistormight utilize a structure similar to (e.g., the same as) the memorycells 208. An example of this configuration is depicted in furtherdetail in FIG. 2B. Collectively, for a given NAND string 206, a unitcolumn structure 256 refers to the elements between its memory cells 208and an upper data line 204, its memory cells 208, and the elementsbetween its memory cells 208 and a pass gate 238, that are connected(e.g., selectively connected) to one another. For example, withreference to FIG. 2A, a unit column structure 256 for a given NANDstring 206 might include its GG gate 220, upper select gate 212, memorycells 208, lower select gate 210 and capacitance 226, connected inseries between an upper data line 204 and a pass gate 238.

The memory array in FIG. 2A might be a quasi-two-dimensional memoryarray and might have a generally planar structure, e.g., where thecommon source 216, NAND strings 206 and upper data lines 204 extend insubstantially parallel planes. Alternatively, the memory array in FIG.2A might be a three-dimensional memory array, e.g., where upper datalines 204 are selectively connected to more than one NAND string 206 andwhere backside gate lines 244 are connected to more than one pass gate238.

A column of the memory cells 208 might be a NAND string 206 or aplurality of NAND strings 206 selectively connected to a given upperdata line 204. A row of the memory cells 208 might be memory cells 208commonly connected to a given word line 202. A row of memory cells 208can, but need not, include all memory cells 208 commonly connected to agiven word line 202.

The memory cells 208 might be programmed as what are often termedsingle-level cells (SLC). SLC may use a single memory cell to representone digit (e.g., one bit) of data. For example, in SLC, a Vt of 2.5V orhigher might indicate a programmed memory cell (e.g., representing alogical 0) while a Vt of −0.5V or lower might indicate an erased memorycell (e.g., representing a logical 1). Memory might achieve higherlevels of storage capacity by including multi-level cells (MLC),triple-level cells (TLC), quad-level cells (QLC), etc., or combinationsthereof in which the memory cell has multiple levels that enable moredigits of data to be stored in each memory cell. For example, MLC mightbe configured to store two digits of data per memory cell represented byfour Vt ranges, TLC might be configured to store three digits of dataper memory cell represented by eight Vt ranges, QLC might be configuredto store four digits of data per memory cell represented by sixteen Vtranges, and so on. While a number of binary digits of data stored in amemory cell is typically an integer value to represent a binary numberof data states per memory cell, a memory cell may be operated to storenon-integer digits of data. For example, where the memory cell isoperated using three Vt ranges, each memory cell might store 1.5 digitsof data, with two memory cells collectively capable of representing oneof eight data states.

The memory cells 208 of a given NAND string 206 might be configured tostore data at a variety of storage densities. For example, a NAND string206 might contain some memory cells (e.g., dummy memory cells) 208configured to store data at a first storage density, e.g., 0 bits permemory cell. Dummy memory cells 208 are typically incorporated into aNAND string 206 for operational advantages, are generally inaccessibleto a user of the memory, and are generally not intended to store userdata. For example, memory cells 208 formed in certain locations of aNAND string 206 might have different operating characteristics thanmemory cells formed in other locations. By operating these memory cellsas dummy memory cells, such differences in operating characteristicsmight generally be mitigated. In addition, dummy memory cells can beused to buffer select gates from high voltage levels that might beapplied to principal memory cells (e.g., those memory cells intended tostore user data) during certain operations. A NAND string 206 mightfurther contain other memory cells 208 configured to store data at oneor more additional (e.g., higher) storage densities.

FIG. 2B is another schematic of a portion of an array of memory cells200B as could be used in a memory of the type described with referenceto FIG. 1, e.g., as a portion of array of memory cells 104, according toanother embodiment. Like numbered elements in FIG. 2B correspond to thedescription as provided with respect to FIG. 2A. For clarity, certainelements are not numbered, although their identity would be apparentwith reference to depictions in FIG. 2A. FIG. 2B provides additionaldetail of one example of the structure of the capacitances 226 as wellas the incorporation of a dummy unit column structure 257 in addition tounit column structures, e.g., principal unit column structures, 256.

The unit column structures 256 ₀ to 256 ₇, along with the dummy unitcolumn structure 257, might be part of a block of memory cells sharingthe same word lines 202. The unit column structures 256 ₀ to 256 ₃ mightbe part of a first sub-block of memory cells 262 ₀ of the block ofmemory cells corresponding to backside gate lines 244 ₀ to 244 ₃. Theunit column structures 256 ₄ to 256 ₇ might be part of a secondsub-block of memory cells 262 ₁ of the block of memory cellscorresponding to backside gate lines 244 ₄ to 244 ₇. The dummy unitcolumn structure 257 might have the same association to a pass gate 238as the unit column structures 256 ₀ to 256 ₇, and might have a secondcontrol gate 242 of its associated pass gate 238 connected to a dummybackside gate line 260. Where the dummy unit column structure 257 lack aconnection to an upper data line 204, the first control gate 240 of itsassociated pass gate 238 might be electrically floating, e.g.,permanently electrically floating.

The unit column structures 256 ₀ to 256 ₇ and the dummy unit columnstructure 257 might each include memory cells 208 ₀ to 208 _(N)connected to (e.g., having control gates connected to) the access lines202 ₀ to 202 _(N), respectively. The unit column structures 256 ₀ to 256₇ and the dummy unit column structure 257 might each include selectgates (e.g., lower select gates) 210 ₀ to 210 ₂, which might have thesame structure as the memory cells 208. The select gates 210 ₀ to 210 ₂might be connected to (e.g., have control gates connected to) the selectlines 214 ₀ to 214 ₂, respectively.

The unit column structures 256 ₀ to 256 ₇ and the dummy unit columnstructure 257 might each include an optional compensation gate 211between the select gates 210 and the memory cells 208, and might havethe same structure as the memory cells 208. The compensation gate 211might be connected to (e.g., have its control gate connected to) thecontrol line 213.

The unit column structures 256 ₀ to 256 ₇ and the dummy unit columnstructure 257 might each include capacitances 226 ₀ to 226 _(K), whichmight have the same structure as the memory cells 208. The capacitances226 ₀ to 226 _(K) might be connected to (e.g., have control gatesconnected to) the control lines 228 ₀ to 228 _(K), respectively. Thecontrol gate of the field-effect transistor forming a capacitance 226 ofFIG. 2B might correspond to a first electrode of that capacitance 226,and the channel, e.g., body, of the field-effect transistor forming thatcapacitance 226 might correspond to a second electrode of thatcapacitance 226. In functioning as a capacitance (e.g., a commoncapacitance), the field-effect transistors of the capacitances 226 mightbe operated to apply a same voltage level to each control line 228 ₀ to228 _(K) of each unit column structure 256 ₀ to 256 ₇, which might be2-3V, for example.

The unit column structures 256 ₀ to 256 ₇ and the dummy unit columnstructure 257 might each include a GIDL generator gate 220, which mighthave the same structure as the memory cells 208. The GIDL generatorgates 220 might be connected to (e.g., have control gates connected to)the control line 224. The GIDL generator gates 220 of the unit columnstructures 256 ₀ to 256 ₃ might be connected to (e.g., have source/drainregions connected to) the upper data lines 204 ₀ to 204 ₃, respectively.The GIDL generator gates 220 of the unit column structures 256 ₄ to 256₇ might be connected to (e.g., have source/drain regions connected to)the upper data lines 204 ₃ to 204 ₀, respectively. Although depicted anddescribed, the GIDL generator gates 220 might be eliminated. Because thedummy unit column structure 257 is not intended to store data, it mayhave no connection to an upper data line 204, although connection is notprohibited.

The unit column structures 256 ₀ to 256 ₇ and the dummy unit columnstructure 257 might each include select gates (e.g., upper select gates)212 ₀ to 212 ₂, which might have the same structure as the memory cells208. The select gates 212 ₀ to 212 ₂ of the unit column structures 256 ₀to 256 ₃ might be connected to (e.g., have control gates connected to)the select lines 215 ₀₀ to 215 ₀₂, respectively. The select gates 212 ₀to 212 ₂ of the unit column structures 256 ₄ to 256 ₇ might be connectedto (e.g., have control gates connected to) the select lines 215 ₁₀ to215 ₁₂, respectively. The select gates 212 ₀ to 212 ₂ of the dummy unitcolumn structure 257 might be connected to (e.g., have control gatesconnected to) the dummy select lines 217 ₀ to 217 ₂, respectively.Because the dummy unit column structure 257 is not intended to storedata, the dummy select lines 217 ₀ to 217 ₂ may each be electricallyfloating. For example, a contiguous conductive structure could beformed, from which a first select line 215 (e.g., select line 215 ₀₀), asecond select line 215 (e.g., select line 215 ₁₀), and a dummy selectline 217 (e.g., dummy select line 217 ₀) subsequently might be formed.As one example, isolation regions could be formed in such a contiguousconductive structure to define the first select line 215, the secondselect line 215 and the dummy select line 217, with each select lineelectrically isolated from one another. Alternatively, a singleisolation region could be formed in the contiguous conductive structuresuch that the dummy select line 217 would remain connected to either thefirst select line 215 or the second select line 215, but the firstselect line 215 would be isolated from the second select line 215.

As noted, while the array portions of FIGS. 2A and 2B depicted whatmight be formed in a single plane, three-dimensional structures might beused. FIG. 2C is a perspective conceptualization of a portion of anarray of memory cells 200C over peripheral circuitry 266 as could beused in a memory of the type described with reference to FIG. 1,according to a further embodiment. The structures of FIG. 2A or FIG. 2Bmight represent the unit column structures 256 ₀ to 256 _(M) (e.g.,where M=7 for FIG. 2B) for each sense line 258, e.g., sense lines 258 ₀to 258 _(L). For simplicity, the connections of the unit columnstructures 256 to upper data lines 204 is not depicted in FIG. 2C.

The peripheral circuitry 266 might represent a variety of circuitry foraccessing the memory array 200C. The peripheral circuitry 266 mightinclude complementary circuit elements. For example, the peripheralcircuitry 266 might include both n-channel and p-channel transistorsformed on a same semiconductor substrate, a process commonly referred toas CMOS, or complementary metal-oxide-semiconductors. Although CMOSoften no longer utilizes a strict metal-oxide-semiconductor constructiondue to advancements in integrated circuit fabrication and design, theCMOS designation remains as a matter of convenience.

FIGS. 3A-3E are conceptual depictions of portions of a block of memorycells using array structures such as depicted in FIG. 2A anddemonstrating layouts of backside gate lines 244, sense select lines 248and 252, sense lines 258, common source 216 and lower data lines 254,according to embodiments.

FIG. 3A depicts a top-down view of a memory array 300A having a numberof unit column structures 256, including unit column structures 256 ₀ to256 ₇, which might correspond to the unit column structures 256corresponding to the backside gate lines 244 ₀ to 244 _(M) of FIG. 2A,respectively, where M=7. The memory array 300A further depicts a firstsense select line 248, backside gate lines 244 ₀ to 244 ₇, and a secondsense select line 252 in horizontal orientations, which might correspondto the first sense select line 248, the backside gate lines 244 ₀ to 244_(M), and the second sense select line 252 of FIG. 2A, respectively,where M=7. It is recognized that fewer or more backside gate lines 244could be utilized between the sense select lines 248 and 252, and thatfewer or more unit column structures could be associated with eachbackside gate line 244.

FIG. 3B depicts a top-down view of a memory array 300B, which mightinclude the same memory array structure as the memory array 300A. Thememory array 300B has a number of unit column structures 256, includingunit column structures 256 ₀ to 256 ₇, which might correspond to theunit column structures 256 corresponding to the backside gate lines 244₀ to 244 _(M) of FIG. 2A, respectively, where M=7. The memory array 300Bfurther depicts sense lines 258 ₀ to 258 ₂ in diagonal orientations,which each might individually correspond to the sense line 258 of FIG.2A. It is recognized that fewer or more sense lines 258 could beutilized, and that fewer or more unit column structures could beassociated with each sense line 258. The memory array 300B furtherdepicts a common source 216 in a horizontal orientation connected toeach of the sense lines 258 through a respective contact 366, and lowerdata lines 254 ₀ to 254 ₂ in vertical orientations each connected to arespective sense line 258 ₀ to 258 ₂, respectively, through a respectivecontact 367. It is noted that the lower data lines 254 and the commonsource 216 might be connected to sense lines 258 of additional blocks ofmemory cells (not depicted in FIG. 3B).

FIG. 3C depicts a top-down view of a memory array 300C having a numberof unit column structures 256, including unit column structures 256 ₀ to256 ₃, which might correspond to the unit column structures 256corresponding to the backside gate lines 244 ₀ to 244 _(M) of FIG. 2A,respectively, where M=3. The memory array 300C further depicts a firstsense select line 248, backside gate lines 244 ₀ to 244 ₃, and a secondsense select line 252 in horizontal orientations, which might correspondto the first sense select line 248, the backside gate lines 244 ₀ to 244_(M), and the second sense select line 252 of FIG. 2A, respectively,where M=3. It is recognized that fewer or more backside gate lines 244could be utilized between the sense select lines 248 and 252, and thatfewer or more unit column structures could be associated with eachbackside gate line 244.

FIG. 3D depicts a top-down view of a memory array 300D, which mightinclude the same memory array structure as the memory array 300C. Thememory array 300D has a number of unit column structures 256, includingunit column structures 256 ₀ to 256 ₃, which might correspond to theunit column structures 256 corresponding to the backside gate lines 244₀ to 244 _(M) of FIG. 2A, respectively, where M=3. The memory array 300Dfurther depicts sense lines 258 ₀ to 258 ₄ in diagonal orientations,which each might individually correspond to the sense line 258 of FIG.2A. It is recognized that fewer or more sense lines 258 could beutilized, and that fewer or more unit column structures could beassociated with each sense line 258. The memory array 300D furtherdepicts a common source 216 in a horizontal orientation connected toeach of the sense lines 258 through a respective contact 366, and lowerdata lines 254 ₀ to 254 ₄ in vertical orientations each connected to arespective sense line 258 ₀ to 258 ₄, respectively, through a respectivecontact 367. It is noted that the lower data lines 254 and the commonsource 216 might be connected to sense lines 258 of additional blocks ofmemory cells (not depicted in FIG. 3D).

FIG. 3E depicts a top-down view of a memory array 300E, which mightinclude the same memory array structure as the memory array 300C. Thememory array 300E has a number of unit column structures 256, includingunit column structures 256 ₀ and 256 ₁, which might correspond to theunit column structures 256 corresponding to the backside gate lines 244₀ to 244 _(M) of FIG. 2A, respectively, where M=1. The memory array 300Efurther depicts sense lines 258 ₀ to 258 ₁₁ in vertical orientations,which each might individually correspond to the sense line 258 of FIG.2A. It is recognized that fewer or more sense lines 258 could beutilized, and that fewer or more unit column structures could beassociated with each sense line 258. The memory array 300E might furtherinclude a common source 216 (not depicted in FIG. 3E) in a horizontalorientation connected to each of the sense lines 258 through arespective contact 366 such as depicted in FIG. 3D, and lower data lines254 (not depicted in FIG. 3E) in vertical orientations each connected toa respective sense line 258 through a respective contact 367 such asdepicted in FIG. 3D.

FIGS. 3F-3G are conceptual depictions of a portion of a block of memorycells using an array structure such as depicted in FIG. 2B anddemonstrating a layout of backside gate lines 244, dummy backside gateline 260, sense select lines 248 and 252, common source 216 and lowerdata lines 254, according to an additional embodiment.

FIG. 3F depicts a top-down view of a memory array 300F having a numberof unit column structures 256, including unit column structures 256 ₀ to256 ₇, which might correspond to the unit column structures 256 ₀ to 256₇ of FIG. 2B, respectively. The memory array 300F further has a numberof dummy unit column structures 257, including the dummy unit columnstructure 257′, which might correspond to the dummy unit columnstructure 257 of FIG. 2B. The memory array 300F further depicts a firstsense select line 248, backside gate lines 244 ₀ to 244 ₃, dummybackside gate line 260, backside gate lines 244 ₄ to 244 ₇, and a secondsense select line 252 in horizontal orientations, which might correspondto the first sense select line 248, the backside gate lines 244 ₀ to 244₃, the dummy backside gate line 260, the backside gate lines 244 ₄ to244 ₇, and the second sense select line 252 of FIG. 2B, respectively. Itis recognized that fewer or more backside gate lines 244 and dummybackside gate lines 260 could be utilized between the sense select lines248 and 252, and that fewer or more unit column structures 256 could beassociated with each backside gate line 244 and fewer or more dummy unitcolumn structures 257 could be associated with each dummy backside gateline 260.

FIG. 3G depicts a top-down view of a memory array 300G, which mightinclude the same memory array structure as the memory array 300F. Thememory array 300G has a number of unit column structures 256, includingunit column structures 256 ₀ to 256 ₇, which might correspond to theunit column structures 256 corresponding to the backside gate lines 244₀ to 244 _(M) of FIG. 2A, respectively, where M=7. The memory array 300Gfurther has a number of dummy unit column structures 257, including thedummy unit column structure 257′, which might correspond to the dummyunit column structure 257 of FIG. 2B. The memory array 300G furtherdepicts sense lines 258 ₀ to 258 ₃ in folded orientations, which eachmight individually correspond to the sense line 258 of FIG. 2B. It isrecognized that fewer or more sense lines 258 could be utilized, andthat fewer or more unit column structures could be associated with eachsense line 258. The memory array 300G further depicts a common source216 in a horizontal orientation connected to each of the sense lines 258through a respective contact 366, and lower data lines 254 ₀ to 254 ₃ invertical orientations each connected to a respective sense line 258 ₀ to258 ₃, respectively, through a respective contact 367. It is noted thatthe lower data lines 254 and the common source 216 might be connected tosense lines 258 of additional blocks of memory cells (not depicted inFIG. 3D).

FIG. 4A is a conceptual depiction of a portion of a block of memorycells using an array structure such as depicted in FIGS. 3A and 3B, anddemonstrating a layout of upper data line 204 connectivity, according toan embodiment.

FIG. 4A depicts a top-down view of a memory array 400A having a numberof unit column structures 256, which might correspond to the unit columnstructures 256 of FIGS. 3A and 3B. The memory array 400A further depictsa first sense select line 248, backside gate lines 244 ₀ to 244 ₇, and asecond sense select line 252 in horizontal orientations, which mightcorrespond to the first sense select line 248, the backside gate lines244 ₀ to 244 _(M), and the second sense select line 252 of FIG. 2A,respectively, where M=7. It is recognized that fewer or more backsidegate lines 244 could be utilized between the sense select lines 248 and252, and that fewer or more unit column structures could be associatedwith each backside gate line 244. The memory array 400A further depictssense lines 258 ₀ to 258 ₂ in diagonal orientations, which each mightindividually correspond to the sense line 258 of FIG. 2A. It isrecognized that fewer or more sense lines 258 could be utilized, andthat fewer or more unit column structures could be associated with eachsense line 258. The sense lines 258 might be non-orthogonal to, e.g.,angled in relation to, the backside gate lines 244. The memory array400A further depicts a number of upper data lines 204 in verticalorientations, including upper data lines 204 ₀ to 204 ₂₁. The upper datalines 204 might be orthogonal to the backside gate lines 244.

With reference to the sense line 258 ₂ of FIG. 4A as corresponding tothe sense line 258 of FIG. 2A, the upper data line 204 ₈ of FIG. 4Amight correspond to the upper data line 204 ₀ of FIG. 2A, the upper dataline 204 ₁₀ of FIG. 4A might correspond to the upper data line 204 ₁ ofFIG. 2A, the upper data line 204 ₁₁ of FIG. 4A might correspond to theupper data line 204 ₂ of FIG. 2A, the upper data line 204 ₁₃ of FIG. 4Amight correspond to the upper data line 204 ₃ of FIG. 2A, the upper dataline 204 ₁₆ of FIG. 4A might correspond to the upper data line 204 ₄ ofFIG. 2A, the upper data line 204 ₁₈ of FIG. 4A might correspond to theupper data line 204 ₅ of FIG. 2A, the upper data line 204 ₁₉ of FIG. 4Amight correspond to the upper data line 204 ₆ of FIG. 2A, and the upperdata line 204 ₂₁ of FIG. 4A might correspond to the upper data line 204₇ of FIG. 2A, where M=7. Although upper data lines 204 ₃ to 204 ₆ arenot explicitly depicted in FIG. 2A, it is apparent from the figure thatthe upper data lines 204 of the array of memory cells 200A may benumbered consecutively from upper data line 204 ₀ to upper data line 204_(M). Each of the upper data lines 204 might be connected to one or morerespective unit column structures 256 through respective contacts 464.It is noted that the upper data lines 204 might be connected to unitcolumn structures 256 of additional blocks of memory cells (not depictedin FIG. 4A).

It is noted that a set of upper data lines 204, e.g., upper data lines204 ₄, 204 ₆, 204 ₇, 204 ₉, 204 ₁₂, 204 ₁₄, 204 ₁₅, and 204 ₁₇,connected to unit column structures 256 that are capacitively coupled toone sense line 258, e.g., sense line 258 ₁, may be mutually exclusivefrom a set of upper data lines 204, e.g., upper data lines 204 ₈, 204₁₀, 204 ₁₁, 204 ₁₃, 204 ₁₆, 204 ₁₈, 204 ₁₉, and 204 ₂₁, connected tounit column structures 256 that are capacitively coupled to a differentsense line 258, e.g., adjacent (e.g., immediately adjacent) sense line258 ₂. In this scenario, one or more of the upper data lines 204connected to unit column structures 256 that are capacitively coupled tosense line 258 ₁ may be interleaved with one or more upper data lines204 connected to unit column structures 256 that are capacitivelycoupled to sense line 258 ₂. In addition, a set of upper data lines 204,e.g., upper data lines 204 ₀, 204 ₂, 204 ₃, 204 ₅, 204 ₈, 204 ₁₀, 204₁₁, and 204 ₁₃, connected to unit column structures 256 that arecapacitively coupled to one sense line 258, e.g., sense line 258 ₀, maynot be completely mutually exclusive from a set of upper data lines 204,e.g., upper data lines 204 ₈, 204 ₁₀, 204 ₁₁, 204 ₁₃, 204 ₁₆, 204 ₁₈,204 ₁₉, and 204 ₂₁, connected to unit column structures 256 that arecapacitively coupled to a different sense line 258, e.g., sense line 258₂. In this scenario, there may be no interleaving of upper data lines204 in this case.

FIG. 4B is a conceptual depiction of a portion of a block of memorycells using an array structure such as depicted in FIGS. 3C and 3D, anddemonstrating a layout of upper data line 204 connectivity, according toanother embodiment.

FIG. 4B depicts a top-down view of a memory array 400B having a numberof unit column structures 256, which might correspond to the unit columnstructures 256 of FIGS. 3C and 3D. The memory array 400B further depictsa first sense select line 248, backside gate lines 244 ₀ to 244 ₃, and asecond sense select line 252 in horizontal orientations, which mightcorrespond to the first sense select line 248, the backside gate lines244 ₀ to 244 _(M), and the second sense select line 252 of FIG. 2A,respectively, where M=3. It is recognized that fewer or more backsidegate lines 244 could be utilized between the sense select lines 248 and252, and that fewer or more unit column structures could be associatedwith each backside gate line 244. The memory array 400B further depictssense lines 258 ₀ to 258 ₄ in diagonal orientations, which each mightindividually correspond to the sense line 258 of FIG. 2A. It isrecognized that fewer or more sense lines 258 could be utilized, andthat fewer or more unit column structures could be associated with eachsense line 258. The sense lines 258 might be non-orthogonal to, e.g.,angled in relation to, the backside gate lines 244. The memory array400B further depicts a number of upper data lines 204 in verticalorientations, including upper data lines 204 ₀ to 204 ₂₃. The upper datalines 204 might be orthogonal to the backside gate lines 244.

With reference to the sense line 258 ₄ of FIG. 4B as corresponding tothe sense line 258 of FIG. 2A, the upper data line 204 ₁₆ of FIG. 4Bmight correspond to the upper data line 204 ₀ of FIG. 2A, the upper dataline 204 ₁₈ of FIG. 4B might correspond to the upper data line 204 ₁ ofFIG. 2A, the upper data line 204 ₂₁ of FIG. 4B might correspond to theupper data line 204 ₂ of FIG. 2A, and the upper data line 204 ₂₃ of FIG.4B might correspond to the upper data line 204 ₃ of FIG. 2A, where M=3.It is noted that the upper data lines 204 might be connected to unitcolumn structures 256 of additional blocks of memory cells (not depictedin FIG. 4B).

It is noted that a set of upper data lines 204, e.g., upper data lines204 ₀, 204 ₂, 204 ₅, and 204 ₇, connected to unit column structures 256that are capacitively coupled to one sense line 258, e.g., sense line258 ₀, may be mutually exclusive from a set of upper data lines 204,e.g., upper data lines 204 ₄, 204 ₆, 204 ₉, and 204 ₁₁, connected tounit column structures 256 that are capacitively coupled to a differentsense line 258, e.g., adjacent sense line 258 ₁. In this scenario, oneor more of the upper data lines 204 connected to unit column structures256 that are capacitively coupled to sense line 258 ₀ may be interleavedwith one or more upper data lines 204 connected to unit columnstructures 256 that are capacitively coupled to sense line 258 ₁. Thisrelationship may be true for sets of upper data lines 204 connected tounit column structures 256 that are capacitively coupled to eachremaining sense line 258.

FIG. 4C is a conceptual depiction of a portion of a block of memorycells using an array structure such as depicted in FIGS. 3C and 3E, anddemonstrating a layout of upper data line 204 connectivity, according toa further embodiment.

FIG. 4C depicts a top-down view of a memory array 400C having a numberof unit column structures 256, which might correspond to the unit columnstructures 256 of FIGS. 3C and 3E. The memory array 400C further depictsa first sense select line 248, backside gate lines 244 ₀ to 244 ₃, and asecond sense select line 252 in horizontal orientations, which mightcorrespond to the first sense select line 248, the backside gate lines244 ₀ to 244 _(M), and the second sense select line 252 of FIG. 2A,respectively, where M=3. It is recognized that fewer or more backsidegate lines 244 could be utilized between the sense select lines 248 and252, and that fewer or more unit column structures could be associatedwith each backside gate line 244. The memory array 400C further depictssense lines 258 ₀ to 258 ₁₁ in vertical orientations, which each mightindividually correspond to the sense line 258 of FIG. 2A. It isrecognized that fewer or more sense lines 258 could be utilized, andthat fewer or more unit column structures could be associated with eachsense line 258. The sense lines 258 might be orthogonal to the backsidegate lines 244. The memory array 400C further depicts a number of upperdata lines 204 in vertical orientations, including upper data lines 204₀ to 204 ₂₃. The upper data lines 204 might be orthogonal to thebackside gate lines 244.

With reference to the sense line 258 ₀ of FIG. 4C as corresponding tothe sense line 258 of FIG. 2A, the upper data line 204 ₀ of FIG. 4Cmight correspond to the upper data line 204 ₀ of FIG. 2A, and the upperdata line 204 ₁ of FIG. 4C might correspond to the upper data line 204 ₁of FIG. 2A, where M=1. It is noted that the upper data lines 204 mightbe connected to unit column structures 256 of additional blocks ofmemory cells (not depicted in FIG. 4C).

It is noted that a set of upper data lines 204, e.g., upper data lines204 ₀ and 204 ₁, connected to unit column structures 256 that arecapacitively coupled to one sense line 258, e.g., sense line 258 ₀, maybe mutually exclusive from a set of upper data lines 204, e.g., upperdata lines 204 ₂ and 204 ₃, connected to unit column structures 256 thatare capacitively coupled to a different sense line 258, e.g., adjacent(e.g., immediately adjacent) sense line 258 ₁. In this scenario, theremay be no interleaving of sets of upper data lines 204. Thisrelationship may be true for sets of upper data lines 204 connected tounit column structures 256 that are capacitively coupled to eachremaining sense line 258.

FIG. 4D is a conceptual depiction of a portion of a block of memorycells using an array structure such as depicted in FIGS. 3F and 3G, anddemonstrating a layout of upper data line 204 connectivity, according toa further embodiment.

FIG. 4D depicts a top-down view of a memory array 400D having a numberof unit column structures 256 and dummy unit column structures 257,which might correspond to the unit column structures 256 and dummy unitcolumn structures 257, respectively, of FIGS. 3F and 3G. The memoryarray 400D further depicts a first sense select line 248, backside gatelines 244 ₀ to 244 ₃, dummy backside gate line 260, backside gate lines244 ₄ to 244 ₇, and a second sense select line 252 in horizontalorientations, which might correspond to the first sense select line 248,the backside gate lines 244 ₀ to 244 ₃, the dummy backside gate line260, the backside gate lines 244 ₄ to 244 ₇, and the second sense selectline 252 of FIG. 2B, respectively. It is recognized that fewer or morebackside gate lines 244 and dummy backside gate lines 260 could beutilized between the sense select lines 248 and 252, and that fewer ormore unit column structures 256 could be associated with each backsidegate line 244 and fewer or more dummy unit column structures 257 couldbe associated with each dummy backside gate line 260. The memory array400D further depicts sense lines 258 ₀ to 258 ₃ in folded orientations,which each might individually correspond to the sense line 258 of FIG.2B. It is recognized that fewer or more sense lines 258 could beutilized, and that fewer or more unit column structures 256 and dummyunit column structures 257 could be associated with each sense line 258.The sense lines 258 might be non-orthogonal to, e.g., angled in relationto, the backside gate lines 244. The memory array 400D further depicts anumber of upper data lines 204 in vertical orientations, including upperdata lines 204 ₀ to 204 ₉. The upper data lines 204 might be orthogonalto the backside gate lines 244.

With reference to the sense line 258 ₃ of FIG. 4D as corresponding tothe sense line 258 of FIG. 2B, the upper data line 20420 of FIG. 4Dmight correspond to the upper data line 204 ₀ of FIG. 2B, the upper dataline 204 ₁₈ of FIG. 4D might correspond to the upper data line 204 ₁ ofFIG. 2B, the upper data line 204 ₁₇ of FIG. 4D might correspond to theupper data line 204 ₂ of FIG. 2B, and the upper data line 204 ₁₅ of FIG.4D might correspond to the upper data line 204 ₃ of FIG. 2B. Each of theupper data lines 204 might be connected to one or more respective unitcolumn structures 256 through respective contacts 464.

It is noted that a set of upper data lines 204, e.g., upper data lines204 ₃, 204 ₅, 204 ₆, and 204 ₈, connected to unit column structures 256that are capacitively coupled to one sense line 258, e.g., sense line258 ₀, may be mutually exclusive from a set of upper data lines 204,e.g., upper data lines 204 ₇, 204 ₉, 204 ₁₀, and 204 ₁₂, connected tounit column structures 256 that are capacitively coupled to a differentsense line 258, e.g., adjacent (e.g., immediately adjacent) sense line258 ₁. In this scenario, one or more of the upper data lines 204connected to unit column structures 256 that are capacitively coupled tosense line 258 ₀ may be interleaved with one or more upper data lines204 connected to unit column structures 256 that are capacitivelycoupled to sense line 258 ₁. This relationship may be true for each pairof adjacent sense lines 258.

FIGS. 5A-5N depict an integrated circuit structure, such as a portion ofa sense line (e.g., sense line 258 of FIG. 2A or 2B) and associatedelements, during various stages of fabrication in accordance withembodiments. In FIG. 5A, a conductor 562 might be formed overlying(e.g., on) a dielectric 560. The conductor 562 might be formed of one ormore conductive materials. The conductor 562 might comprise, consist of,or consist essentially of conductively doped polysilicon and/or mightcomprise, consist of, or consist essentially of metal, such as arefractory metal, or a metal-containing material, such as a refractorymetal silicide or a metal nitride, e.g., a refractory metal nitride, aswell as any other conductive material. As one example, the conductor 562might include tungsten (W) formed overlying the dielectric 560 andtitanium nitride (TiN) formed overlying the tungsten. The dielectric 560might comprise, consist of, or consist essentially of an oxide, e.g.,silicon dioxide (SiO₂), and/or may comprise, consist of, or consistessentially of a high-K dielectric material, such as aluminum oxides(AlO_(x)), hafnium oxides (HfO_(x)), hafnium aluminum oxides(HfAlO_(x)), hafnium silicon oxides (HfSiO_(x)), lanthanum oxides(LaO_(x)), tantalum oxides (TaO_(x)), zirconium oxides (ZrO_(x)),zirconium aluminum oxides (ZrAlO_(x)), or yttrium oxide (Y₂O₃), as wellas any other dielectric material. High-K dielectrics as used hereinmeans a material having a dielectric constant greater than that ofsilicon dioxide. The dielectric 560 might further comprise, consist of,or consist essentially of a spin-on dielectric material, e.g., hydrogensilsesquioxane (HSQ), hexamethyldisiloxane, octamethyltrisiloxane, etc.,or a high-density-plasma (HDP) oxide. As one example, the dielectric 560might contain silicon dioxide. The dielectric 560 might be formedoverlying other circuitry, such as the peripheral circuitry 266 of FIG.2C.

In FIG. 5B, the conductor 562 might be patterned to define a lower dataline 254. Patterning might include forming a photolithographic mask (notdepicted) overlying (e.g., on) the conductor 562 to define areas forremoval, followed by a removal process, such as anisotropic etching, forexample. The mask might subsequently be removed, such as by an ashingprocess, for example.

In FIG. 5C, a dielectric 564 might be formed overlying (e.g., on) thedielectric 560 and the lower data line 254. The dielectric 564 mightcontain one or more dielectric materials, e.g., dielectric materialssuch as described with reference to the dielectric 560. As one example,the dielectric 564 might contain silicon dioxide. A conductor 566 mightbe formed overlying (e.g., on) the dielectric 564. The conductor 566might contain one or more conductive materials, e.g., conductivematerials such as described with reference to the conductor 562. As oneexample, the conductor 566 might contain tungsten. A dielectric 568might be formed overlying (e.g., on) the conductor 566. The dielectric568 might contain one or more dielectric materials, e.g., dielectricmaterials such as described with reference to the dielectric 560. As oneexample, the dielectric 568 might contain silicon dioxide. As a furtherexample, the dielectric 568 might include a structure of SiO₂/SiN/SiO₂,commonly referred to as ONO. A sacrificial material 570 might be formedoverlying (e.g., on) the dielectric 568. The sacrificial material 570might contain a material that can be subjected to removal withoutsignificantly affecting the material(s) of the dielectric 568. As oneexample, the sacrificial material 570 might contain silicon nitride(SiN).

In FIG. 5D, the conductor 566, dielectric 568 and sacrificial material570 might be patterned to define backside gate lines 244 ₀₀ to 244 ₀₂,first sense select line 248 ₀₀, and first select line 248 ₁₀, along withinstances of the dielectric 568 and sacrificial material 570 overlyingeach one. For example, a patterned mask might be formed overlying thesacrificial material 570 defining areas for removal, and an anisotropicremoval process, e.g., reactive ion etching (RIE), might be used todefine the various instances. Spaces or voids between these instancesmight be filled with a dielectric 572. The dielectric 572 might containone or more dielectric materials, e.g., dielectric materials such asdescribed with reference to the dielectric 560. As one example, silicondioxide could be formed overlying the resulting structure afterpatterning, and chemical-mechanical polishing (CMP) could be used toremove any excess silicon dioxide overlying the instances of thesacrificial material 570 to produce the structure depicted in FIG. 5D.

The backside gate lines 244 ₀₀ to 244 ₀₂ of FIG. 5D might correspond tothe backside gate lines 244 ₀ to 244 ₂ of FIG. 2A or 2B for a firstblock of memory cells. The first sense select line 248 ₀₀ of FIG. 5Dmight correspond to the first sense select line 248 of FIG. 2A or 2B forthe first block of memory cells. The first sense select line 248 ₁₀ ofFIG. 5D might correspond to the first sense select line 248 of FIG. 2Aor 2B for a second block of memory cells sharing a connection to thesame lower data line 254.

In FIG. 5E, a via might be formed, e.g., using RIE, in one of theinstances of the dielectric 572 and filled with conductive material toform a contact 574 to the lower data line 254. The contact 574 mightcontain one or more conductive materials, e.g., conductive materialssuch as described with reference to the conductor 562. For oneembodiment, the contact 574 might include conductively-doped polysilicon(e.g., an N+ type conductivity) formed overlying the lower data line 254and titanium nitride (TiN) formed overlying the conductively-dopedpolysilicon. In FIG. 5F, the instances of the sacrificial material 570might be removed, e.g., using an isotropic removal process, such aschemical or plasma etching, to define voids 576.

In FIG. 5G, a semiconductor 578 might be formed overlying (e.g., on),the instances of the dielectric 568, the instances of the dielectric572, and the contact 574. The semiconductor 578 might comprise, consistof, or consist essentially of polysilicon, single-crystal silicon oramorphous silicon, as well as any other semiconductive material, such asgermanium, silicon-germanium, or silicon-germanium-carbonsemiconductors. The semiconductor 578 might be formed, for example,using chemical vapor deposition (CVD), low-pressure CVD (LPCVD),physical vapor deposition (PVD) or atomic layer deposition (ALD). Thesemiconductor might have a conductivity type, e.g., a first conductivitytype. As one example, the semiconductor 578 might contain amorphoussilicon. The semiconductor 578 might be doped during or followingformation. As one example, the semiconductor 578 might be a p-typesemiconductor. For example, diborane (B₂H₆) might be added to thereaction gases of a CVD process to form the amorphous silicon in orderto incorporate sufficient boron into the semiconductor 578 to achieve adesired threshold voltage of a future pass gate 238, e.g., a dopantconcentration of 1E18/cm³. As an alternate example, the semiconductor578 might be an n-type semiconductor. For example, phosphine (PH₃) mightbe added to the reaction gases of a CVD process to form the amorphoussilicon in order to incorporate sufficient phosphorus into thesemiconductor 578 to achieve a desired threshold voltage of a futurepass gate 238, e.g., a dopant concentration of 5E18/cm³. Although notdepicted, the semiconductor 578 might be patterned to define a futuresense line 258.

In FIG. 5H, instances of a dielectric 580 might be formed overlying(e.g., on) the semiconductor 578 and filling the voids 576. Thedielectric 580 might contain one or more dielectric materials, e.g.,dielectric materials such as described with reference to the dielectric560. As one example, silicon dioxide could be formed overlying thesemiconductor 578, and chemical-mechanical polishing (CMP) could be usedto remove any excess silicon dioxide overlying the semiconductor 578 toproduce the structure depicted in FIG. 5H.

In FIG. 5I, portions of the semiconductor 578 might be conductivelydoped using a dopant impurity of a second conductivity type, which mightbe the same or different than the first conductivity type, e.g., to formsource/drain regions. For purposes herein, a dopant impurity is an ion,element or molecule, or some combination of ions, elements and/ormolecules, added to the semiconductor 578 to impart bulk conductivity toaffected portions. Such doping might involve the acceleration of thedopant impurity, as depicted conceptually by arrows 582. As one example,the dopant impurity might be an n-type impurity, such as ions of arsenic(As), antimony (Sb), phosphorus (P) or another n-type impurity. Examplesof such doping processes might include plasma doping (PLAD) and/orbeam-line implantation. An anneal process might be used to diffuse theimplanted dopant impurity within portions of the semiconductor 578 notcovered by the dielectric 580, thereby defining instances ofsemiconductor (e.g., channels) 584 having the first conductivity typeand instances of conductively-doped semiconductor 586 having the secondconductivity type. For example, an instance of semiconductor 584overlying a backside gate line 244 or sense select line 248 might formone channel region for a future pass gate 238 or first sense select gate246, respectively, having the backside gate line 244 or sense selectline 248, respectively, as its control gate and a corresponding instanceof the dielectric 568 as its gate dielectric. Continuing with theexample, instances of the conductively-doped semiconductor 586 on eitherside of that backside gate line 244 or sense select line 248 might formsource/drain regions for that pass gate 238 or first sense select gate246, respectively. It is noted that the doping level of the instances ofconductively-doped semiconductor 586 might be one or more orders ofmagnitude higher than the doping level of the instances of semiconductor584. As one example having a semiconductor 578 having a p-typeconductivity, the doping level of the instances of conductively-dopedsemiconductor 586 might be 3E19/cm{circumflex over ( )}3 compared to adoping level of the instances of semiconductor 584 of 1E18/cm³. Forother embodiments, such as embodiments having a semiconductor 578 havingan n-type conductivity, additional doping might be eliminated, such thatthe doping level of the instances of semiconductor 586 and the dopinglevel of the instances of semiconductor 584 might each remain at5E18/cm³ and of the same conductivity type. For such embodiments, adielectric 568 having an ONO or similar charge trap structure mightallow for programming to adjust a threshold voltage of the pass gate238.

In FIG. 5J, a semiconductor 588 might be formed overlying (e.g., on) theinstances of dielectric 580 and the exposed portions of the instances ofconductively-doped semiconductor 586. The semiconductor 588 mightcomprise, consist of, or consist essentially of polysilicon,single-crystal silicon or amorphous silicon, as well as any othersemiconductive material, such as germanium, silicon-germanium, orsilicon-germanium-carbon semiconductors. The semiconductor 588 might beformed such as described with reference to the semiconductor 578, andmight have the same conductivity type, e.g., the first conductivitytype, or a different conductivity type, e.g., the second conductivitytype. As one example, the semiconductor 588 might be an p-type amorphoussilicon. For other embodiments, the semiconductor 588 might be an n-typeamorphous silicon. For some embodiments, the semiconductor 588 mighthave a doping level of 5E18/cm³. Where the semiconductor 588 and theconductively-doped semiconductor 586 have the same conductivity type,the resulting transistor might be a depletion mode or normally-ontransistor. Where the semiconductor 588 and the conductively-dopedsemiconductor 586 have different conductivity types, the resultingtransistor might be an enhancement mode or normally-off transistor, or adepletion mode or normally-on transistor. For some embodiments, thesemiconductor 588 might be formed prior to the doping described withreference to FIG. 5I, and may receive doping concurrently with theconductively-doped semiconductor 586. As used herein, a first act and asecond act occur concurrently when the first act occurs simultaneouslywith the second act for at least a portion of a duration of the secondact.

A dielectric 590 might be formed overlying (e.g., on) the semiconductor588. The dielectric 590 might contain one or more dielectric materials,e.g., dielectric materials such as described with reference to thedielectric 560. As one example, the dielectric 590 might contain silicondioxide. Alternatively, or in addition, the dielectric 590 might containa high-K dielectric. A sacrificial material 592 might be formedoverlying (e.g., on) the dielectric 590. The sacrificial material 592might contain a material that can be subjected to removal withoutsignificantly affecting the material(s) of the dielectric 590. For oneexample, the sacrificial material 592 might contain silicon nitride(SiN).

In FIG. 5K, the semiconductor 588, dielectric 590 and sacrificialmaterial 592 might be patterned to define instances of semiconductor(e.g., channels) 589, along with instances of the dielectric 590 andsacrificial material 592 overlying each one. For example, a patternedmask might be formed overlying the sacrificial material 592 definingareas for removal, and an anisotropic removal process, e.g., reactiveion etching (REI), might be used to define the various instances. Spacesor voids between these instances might be filled with a dielectric 594.The dielectric 594 might contain one or more dielectric materials, e.g.,dielectric materials such as described with reference to the dielectric560. As one example, silicon dioxide could be formed overlying theresulting structure, and chemical-mechanical polishing (CMP) could beused to remove any excess silicon dioxide overlying the instances of thesacrificial material 592 to produce the structure depicted in FIG. 5K.For some embodiments, exposed portions of the conductively-dopedsemiconductor 586 may receive additional doping of a same conductivitytype prior to forming the dielectric 594.

In FIG. 5L, the instances of the sacrificial material 592 might beremoved, e.g., using an isotropic removal process, such as chemical orplasma etching, to define voids 596. In FIG. 5M, plugs 598 ₀₀ to 598 ₀₂might be formed in the voids 596. As one example, conductive material(e.g., titanium nitride over tungsten) could be formed overlying (e.g.,on) the instances of the dielectric 590 and the instances of thedielectric 594 to fill the voids 596, and CMP could be used to removeany excess conductive material overlying the instances of the dielectric594 to produce the structure depicted in FIG. 5M. The plugs 598 might beformed of a material selected to act as a stop layer during subsequentprocessing as described with reference to FIG. 6B, and may besacrificial and removed during subsequent processing, such as describedwith reference to FIG. 6C. The bracket 600 identifies a portion of theintegrated circuit structure of FIG. 5M that might be depicted in FIGS.6A-6F.

While FIGS. 5A-5M depicted an integrated circuit structure that mightcorrespond to a portion of a sense line (e.g., sense line 258 of FIG. 2Aor 2B) and associated elements at an end adjacent a lower data line 254,FIG. 5N might depict another portion of that sense line (e.g., senseline 258 of FIG. 2A or 2B) and associated elements at an opposing end,e.g., an end adjacent a common source 216. The structure of FIG. 5Nmight be formed concurrently with the structure of FIG. 5M, and depictsbackside gate lines 244 _(0(M-1)) and 244 _(0M) and corresponding plugs598 _(0(M-1)) and 598 _(0M), respectively, a second select line 252, anda common source 216 and its connection to an instance ofconductively-doped semiconductor 586 through a conductive contact 574.The common source 216 and second sense select line 252 might be formedfrom the conductor 566 (e.g., as in FIGS. 5C-5D) concurrently with thefirst sense select line 248 and the backside gate lines 244.

FIGS. 6A-6F depict an integrated circuit structure, which mightcorrespond to a portion of a unit column structure 256 of FIG. 2A or 2Bduring various stages of fabrication in accordance with additionalembodiments. FIGS. 6A-6F might be used to depict further processingfollowing formation of the structure of FIG. 5M, for example. It will beunderstood that FIGS. 6A-6F could equally apply to the formation of adummy unit column structure 257, where the backside gate line 244 x ofFIGS. 6A-6F is instead a dummy backside gate line 260.

In FIG. 6A, the backside gate line 244 x might correspond to a secondcontrol gate 242 of a pass gate 238 x, where X might be any integervalue from zero to M, with a number of unit column structures 256associated with a sense line 258 being equal to M+1. The pass gate 238 xmight further include channels formed of the semiconductors 584 and 589,gate dielectrics formed of the dielectrics 568 and 590, and source/drainregions formed of the conductively-doped semiconductors 586. A firstcontrol gate 240 of the pass gate 238 x might not yet be formed, but itsfuture location might correspond to the location of the plug 598 x.

In FIG. 6A, instances of a dielectric 602 (e.g., 6020 to 6024) andinstances of a sacrificial material 604 (e.g., 6040 to 6043) might beformed in an alternating manner overlying (e.g., on) the plug 598 x andthe dielectric 594. The instances of the dielectric 602 might eachcontain one or more dielectric materials, e.g., dielectric materialssuch as described with reference to the dielectric 560. As one example,the instances of the dielectric 602 might contain silicon dioxide. Theinstances of the sacrificial material 604 might contain a material thatcan be subjected to removal without significantly affecting thematerial(s) of the dielectric 602. As one example, the instances of thesacrificial material 604 might contain silicon nitride. Additionalinstances of the dielectric 602 and instances of the sacrificialmaterial 604 might be formed, depending upon the number of transistorsintended to be formed, e.g., memory cells, GIDL generator gates, selectgates and capacitances, for a future unit column structure. While allintended instances of the dielectric 602 and instances of thesacrificial material 604 might be formed before proceeding to theprocessing of FIG. 6B, typical processing of such stacked structuresmight be performed in stages as the aspect ratio of the via 606 mightbecome too large to form the entire structure reliably as a contiguousentity.

In FIG. 6B, a via 606 might be formed through the instances of thedielectric 602 and the instances of the sacrificial material 604, usingthe plug 598 x as a stop. For example, an anisotropic removal process,e.g., RIE, might be used with the plug 598 x acting as an etch stop. Assuch, the via 606 might extend to the surface of the plug 598 x orbelow.

In FIG. 6C, the plug 598 x might be removed following formation of thevia 606 to complete a void 607. A channel material structure 610 mightbe formed to line the sidewalls of the void 607, e.g., formed along thesidewalls of the instances of the dielectric 602 and the instances ofthe sacrificial material 604, as well as along sidewalls of thedielectric 594 and a surface (e.g., upper surface) of the dielectric590. For some embodiments, the dielectric 590 might also be removedprior to forming the channel material structure 610, and portions of thechannel material structure 610 could function as a gate dielectric tothe resulting pass gate 238.

The portion 608 of the channel material structure 610 is depicted infurther detail in the expanded portion 608′. As depicted, the channelmaterial structure 610 might include a charge-blocking material 612formed to line the void 607, a charge-storage material 614 might beformed on the charge-blocking material 612, a dielectric (e.g., gatedielectric) 616 might be formed on the charge-storage material 614, anda channel material (e.g., a semiconductor) 618 might be formed on thedielectric 616. The charge-storage material 614 might contain adielectric or conductive charge-storage material. The charge-storagematerial 614 might further contain both dielectric and conductivematerials, e.g., conductive nano-particles in a dielectric bulkmaterial. For charge-storage material 614 containing a conductivematerial as its bulk, or contiguous, structure, resulting memory cellsmight typically be referred to as floating-gate memory cells. Forcharge-storage material 614 containing a dielectric material as itsbulk, or contiguous, structure, resulting memory cells might typicallybe referred to as charge-trap memory cells. For one embodiment, thecharge-blocking material 612, charge-storage material 614 and dielectric616 might form an ONO structure. The channel material 618 might be aportion of a contiguous semiconductor structure for each transistor ofthe future unit column structure, or might otherwise be electricallyconnected, which might include selectively electrically connected, tochannels of each transistor of the future unit column structure.

The charge-blocking material 612 might function as a charge-blockingnode for future memory cells and other transistors of the unit columnstructure having a same structure, and might include one or moredielectric materials, such as described with reference to the dielectric560. For example, the charge-blocking material 612 might include ahigh-K dielectric material. The charge-storage material 614 mightfunction as a charge-storage node for future memory cells and othertransistors of the unit column structure having a same structure, andmight include one or more conductive or dielectric materials capable ofstoring a charge. For example, the charge-storage material 614 mightinclude polysilicon, which might be conductively doped. The dielectric616 might function as a gate dielectric for future memory cells andother transistors of the unit column structure having a same structure,and might include one or more dielectric materials such as describedwith reference to the dielectric 568. For example, the dielectric 568might include silicon dioxide. The channel material 618 might functionas a channel for future memory cells and other transistors of the unitcolumn structure having a same structure, and might include one or moresemiconductors such as described with reference to the semiconductor578.

In FIG. 6D, the instances of sacrificial material 604 might be removedto define voids 620, e.g., voids 620 ₀ to 620 ₃. The removal mightinclude an isotropic removal process, e.g., a plasma etching process. InFIG. 6E, instances of an optional charge-blocking material 622, e.g.,instances of charge-blocking material 622 ₀-622 ₃, might be formed toline the voids 620, e.g., voids 620 ₀ to 620 ₃, respectively. Theinstances of charge-blocking material 622 might include one or moredielectric materials, such as described with reference to the dielectric560, and might include a high-K dielectric material. For embodimentswith the charge-blocking material 612, the instances of charge-blockingmaterial 622 might function as an additional charge-blocking material ofa charge-blocking node for future memory cells and other transistors ofthe unit column structure having a same structure. For embodimentswithout the charge-blocking material 612, the instances ofcharge-blocking material 622 might function individually as acharge-blocking node for future memory cells and other transistors ofthe unit column structure having a same structure. For embodiments withthe charge-blocking material 612, and without the instances ofcharge-blocking material 622, the charge-blocking material 612 mightfunction individually as a charge-blocking node for future memory cellsand other transistors of the unit column structure having a samestructure. Instances of a conductor 624, e.g., instances of a conductor624 ₀ to 624 ₃, might be formed to fill the voids 620, e.g., voids 620 ₀to 620 ₃, respectively. The instances of the conductor 624 might containone or more conductive materials, e.g., conductive materials such asdescribed with reference to the conductor 562.

A transistor might be formed at each intersection of an instance of theconductor 624 and the channel material 618, where an instance of theconductor 624 might function as a control gate of the transistor,adjacent channel material 618 might function as a channel of thetransistor, and an instance of charge-blocking material 622 and/orcharge-blocking material 612, charge-storage material 614, anddielectric 616 between the instance of the conductor 624 and theadjacent channel material 618 might function as a charge-blocking node,charge-storage node and gate dielectric, respectively, of thattransistor. Such transistors could include memory cells 208, GIDLgenerator gates 220, upper select gates 212, lower select gates 210,and/or capacitances 226 for a future unit column structure, for example.The channel material 618 adjacent the dielectric 590 might function asthe first control gate 240 of a pass gate 238 having the semiconductor589 as its channel and the dielectric 590 as its gate dielectric, forexample.

FIG. 6F might depict an opposing end of the portion of a unit columnstructure depicted in FIG. 6E. For example, while FIG. 6E might depictan end of a unit column structure nearest an associated pass gate 238,FIG. 6F might depict an end of that unit column structure nearest anassociated upper data line 204. FIG. 6F might depict further alternatinginstances of the dielectric 602, e.g., instances of dielectric 602_(K−5) to 602 _(K+1), instances of charge-blocking material 622, e.g.,instances of charge-blocking material 622 _(K−5) to 622 _(K), andinstances of conductor 624, e.g., instances of conductor 624 _(K−5) to624 _(K), where K might equal a total number of memory cells 208(including any dummy memory cells), GIDL generator gates 220, upperselect gates 212, lower select gates 210, and capacitances 226 in a unitcolumn structure, minus 1. The channel material structure 610 depictedin FIG. 6F might be contiguous with the channel material structure 610depicted in FIG. 6E. The upper data line 204 might be connected to thechannel material 618 of the channel material structure 610 through acontact 464. The contact 464 might contain one or more conductivematerials, e.g., conductive materials such as described with referenceto the conductor 562. For some embodiments, the contact 464 mightcontain an n⁺-type conductively-doped polysilicon. For otherembodiments, the contact 464 might include an n⁺-type conductively-dopedpolysilicon formed overlying the channel material structure 610,titanium nitride (TiN) formed overlying the n⁺-type conductively-dopedpolysilicon, and tungsten (W) formed overlying the titanium nitride. Forfurther embodiments, the upper portion of the channel material 618 ofthe channel material structure 610 might be doped to an n⁺-typeconductivity, and the contact 464 might include titanium nitride (TiN)formed overlying the channel material structure 610, and tungsten (W)formed overlying the titanium nitride. While FIGS. 6A-6F depicted anexample method of forming a plurality of series-connected and stackedtransistors, each corresponding to a respective conductor 624 ₀ to 624_(K), other methods of forming such transistors, as well as othertransistor structures whose channel material could function as anelectrode of a capacitor, could be used with various embodiments.

It is noted that the channel material 618 of a unit column structure,such as depicted in FIGS. 6A-6F, is dead-headed at the bottom of thevoid 607. As such, the channels of the various transistors of the unitcolumn structure might be selectively connected to only one voltagenode, e.g., an upper data line 204, for sourcing or sinking a current tothose channels, and would be electrically floating (e.g., permanentlyelectrically floating) but for its connection (e.g., selectiveconnection) to an upper data line 204. This is in stark contrast to atraditional NAND structure where the channel of the memory cells couldbe selectively connected to voltage nodes at both ends of the string ofseries-connected memory cells, e.g., selectively connected to a dataline at one end and selectively connected to a source at the other end.

FIGS. 7A-7J depict orthogonal views of various structures for senselines in accordance with embodiments. FIG. 7B depicts a view of thestructure of FIG. 7A taken along line B-B′. FIG. 7D depicts a view ofthe structure of FIG. 7C taken along line D-D′. FIG. 7F depicts a viewof the structure of FIG. 7E taken along line F-F′. FIG. 7H depicts aview of the structure of FIG. 7G taken along line H-H′. FIG. 7J depictsa view of the structure of FIG. 7I taken along line J-J′.

While the semiconductor 588 was patterned concurrently with thedielectric 590 and sacrificial material 592 to define an instance ofsemiconductor 589 to have the same footprint as a corresponding futurechannel material structure 610, FIGS. 7A and 7B depict an example wherethe semiconductor 588 first might be patterned concurrently with thesemiconductor 578, and then patterned again concurrently with thedielectric 590 and sacrificial material 592. In this manner, thephysical width of the semiconductor 589 (e.g., a distance left to rightin FIG. 7B) might be the same as the semiconductor 584 andconductively-doped semiconductor 586 for a given pass gate 238. Thephysical length of the semiconductor 589 (e.g., a distance left to rightin FIG. 7A) might be different than the physical length of thesemiconductor 584, but may provide a similar electrical channel lengthas the semiconductor 584 due to the conductivity level of theconductively-doped semiconductor 586.

In FIGS. 7C and 7D, the semiconductor 578 might be formed as a flatlayer instead of a serpentine layer as depicted in FIG. 5G. Theconductively-doped semiconductor 586 could be formed overlying thesemiconductor 578 as an additional layer of semiconductor material,e.g., conductively-doped polysilicon, and subsequently patterned todefine blocks of conductively-doped semiconductor 586 as depicted inFIGS. 7C and 7D. These blocks of conductively-doped semiconductor 586might act as source/drain regions of a pass gate 238, and may extend toa next pass gate 238 or to a first sense select gate 246 or a secondsense select gate 250. Patterning of a semiconductor 588 to define aninstance of semiconductor 589 might be performed as described withreference to FIGS. 7A and 7B to produce the structure depicted in FIGS.7C and 7D. The added bulk of the conductively-doped semiconductor 586 inFIGS. 7C-7D might mitigate the risk of damage to the conductively-dopedsemiconductor 586 during patterning of the semiconductor 588 to form thesemiconductor 589 relative to the embodiment of FIGS. 7A-7B.

In FIGS. 7E and 7F, the semiconductor 578 might be formed as a flatlayer instead of a serpentine layer as depicted in FIG. 5G, andselectively conductively doped to define the instances of thesemiconductor 584 and conductively-doped semiconductor 586. An instanceof the semiconductor 584 might serve as a channel for both control gatesof a resulting pass gate 238, e.g., without formation of a semiconductor589.

In FIGS. 7G and 7H, the semiconductor 578 might be formed around raisedportions of the backside gate line 244X, and selectively conductivelydoped to define the instances of the semiconductor 584 andconductively-doped semiconductor 586. An instance of the semiconductor584 might serve as a channel for both control gates of a resulting passgate 238, e.g., without formation of a semiconductor 589.

In FIGS. 7I and 7J, the two channels of a pass gate 238 might be formedof separate contiguous semiconductor materials. For example, theprocessing of FIGS. 5C and 5D might proceed without forming thesacrificial material 570, and an instance of semiconductor 578 might beformed after patterning the conductor 566 and the dielectric 568, andforming the dielectric 572, to be overlying the instances of thedielectric 568 and the dielectric 572. This instance of semiconductor578 might be selectively conductively doped to define the instances ofthe semiconductor 584 _(lower) and conductively-doped semiconductor 586_(lower). A dielectric might then be formed overlying the instances ofthe semiconductor 584 _(lower) and conductively-doped semiconductor 586_(lower), and patterned to define an instance of dielectric 726 for eachpass gate 238. Another instance of semiconductor 578 might then beformed overlying the dielectric 726 and the exposed instances ofconductively-doped semiconductor 586. This instance of semiconductor 578might be selectively conductively doped to define the instances of thesemiconductor 584 _(upper) and conductively-doped semiconductor 586_(upper).

FIGS. 8A-8C depict an integrated circuit structure during various stagesof fabrication in accordance with an embodiment. FIG. 8A might depict astructure similar to that shown in FIG. 6A, and might be formed in asimilar manner. However, a conductively-doped polysilicon 830, and anoptional barrier layer 832 might be formed between the dielectric 590and the plug 598. For example, the conductively-doped polysilicon 830might be formed to line the voids 596 in FIG. 5L, and then the plug 598might be formed to fill a remaining portion of a void 596. Optionally,the barrier layer 832 might be formed between the conductively-dopedpolysilicon and the plug 598. In FIG. 8B, the void 607 might be formedin a manner similar to that described with reference to FIGS. 6B and 6C,including removal of the plug 598 and the barrier layer 832. The channelmaterial structure might then be formed as described with reference toFIG. 6C, including the charge-blocking material 612, charge-storagematerial 614, dielectric 616, and channel material 618. In thisembodiment, the first control gate 240 of a pass gate 238 might be adiscrete conductive element (e.g., conductively-doped polysilicon 830)between the electrode of a capacitance 226 (e.g., a channel of afield-effect transistor or channel material 618) and a channel (e.g.,semiconductor 589) of that pass gate 238.

Although the example of FIGS. 8A-8C utilizes conductively-dopedpolysilicon, other conductive materials could also be utilized, such asconductive materials described with reference to the conductor 562. Inaddition, although the example of FIGS. 8A-8C depicts an embodimentutilizing two discrete channels of a pass gate 238, e.g., forming aseparate semiconductor 589, such structures could also be used inembodiments utilizing a single channel. Furthermore, although theconductively-doped polysilicon 830 was formed to be below, and adjacentsidewalls of, the channel material 618, it might be formed withoutextending to a point adjacent the sidewalls of the channel material 618.

FIGS. 9A-9E depict an integrated circuit structure during various stagesof fabrication in accordance with another embodiment. FIG. 9A mightdepict a structure similar to that shown in FIG. 6A, and might be formedin a similar manner. However, the dielectric 594 might be formed as afirst dielectric 940 ₀, a second dielectric 942, and a third dielectric940 ₁. The dielectrics 940 ₀ and 940 ₁ might be a same dielectricmaterial, while the dielectric 942 might be a different dielectricmaterial. For example, the dielectrics 940 ₀ and 940 ₁ might containsilicon carbon nitride (SiCN), while the dielectric 942 might containsilicon dioxide. In addition, a conductively-doped polysilicon 944 mightbe formed between the dielectric 590 and the plug 598. For example, theconductively-doped polysilicon 944 might be formed to fill a bottom of avoid 596 in FIG. 5L, and then the plug 598 might be formed to fill aremaining portion of the void 596. Optionally, a barrier layer (notshown) might be formed between the conductively-doped polysilicon 944and the plug 598. In FIG. 9B, the void 607 might be formed in a mannersimilar to that described with reference to FIGS. 6B and 6C, includingremoval of the plug 598 and any barrier layer.

In FIG. 9C, the channel material structure might then be formed asdescribed with reference to FIG. 6C, including the charge-blockingmaterial 612, charge-storage material 614, dielectric 616, and channelmaterial 618. In FIG. 9D, the dielectric 942 might be removed, alongwith exposed portions of the charge-blocking material 612,charge-storage material 614, and dielectric 616 sufficient to remove thethickness of these materials, e.g., which might leave a recessed portionbetween the channel material 618 and the conductively-doped polysilicon944. For example, an isotropic etch process could be used with achemistry selective to the materials for removal over materials of thechannel material 618, conductively-doped polysilicon 944 and thedielectrics 940 ₀ and 940 ₁. In FIG. 9E, a conductively-dopedpolysilicon 946 might be selectively grown on exposed surfaces of thechannel material 618 and the conductively-doped polysilicon 944 tobridge the gap, and form an electrical connection, between the channelmaterial 618 and the conductively-doped polysilicon 944. In thisembodiment, the first control gate 240 of a pass gate 238 might be adiscrete conductive element (e.g., conductively-doped polysilicon 944and 946) between the electrode of a capacitance 226 (e.g., a channel ofa field-effect transistor or channel material 618) and a channel (e.g.,semiconductor 589) of that pass gate 238. In this manner, the channelmaterial 618 might be electrically connected to the first gate 240 of apass gate 238 rather than be capacitively coupled to the first gate 240.

Although the example of FIGS. 9A-9E depicts an embodiment utilizing twodiscrete channels of a pass gate 238, e.g., forming a separatesemiconductor 589, such structures could also be used in embodimentsutilizing a single channel. In addition, although the conductively-dopedpolysilicon 946 was formed to be below, and adjacent sidewalls of, thechannel material 618, it might be formed without extending to a pointadjacent the sidewalls of the channel material 618. For example, formingthe dielectric 940 ₁ to be thicker could restrict formation of theconductively-doped polysilicon 946 to be solely below the channelmaterial 618.

FIGS. 10A and 10B depict an integrated circuit structures at aparticular stage of fabrication in accordance with further embodiments.The embodiment of FIG. 10A might depict a structure similar to thatshown in FIG. 6C, and might be formed in a similar manner. However, ahigh-K dielectric 1050 might be formed between the semiconductor 589 andthe plug 598. For example, the high-K dielectric 1050 might be formed toline a lower portion (e.g., a bottom) of a void 596 in FIG. 5L, and thenthe plug 598 might be formed to fill a remaining portion of that void596. For some embodiments, the dielectric 590 might be omitted, with thehigh-K dielectric 1050 serving as the gate dielectric of the firstcontrol gate 240 of a pass gate 238. The void 607 might be formed in amanner similar to that described with reference to FIGS. 6B and 6C,including removal of the plug 598. And the channel material structure610 might then be formed as described with reference to FIG. 6C.

The embodiment of FIG. 10B might also depict a structure similar to thatshown in FIG. 6C, and might be formed in a similar manner. However, ahigh-K dielectric 1050 might be formed between the semiconductor 589 andthe plug 598. For example, the high-K dielectric 1050 might be formed toline a void 596 in FIG. 5L e.g., the bottom and sidewalls of the void596, and then the plug 598 might be formed to fill a remaining portionof that void 596. For some embodiments, the dielectric 590 might beomitted, with the high-K dielectric 1050 serving as the gate dielectricof the first control gate 240 of a pass gate 238. For other embodiments,the dielectric 590 might be de minimis, e.g., on the order of 1 nm inthickness. The void 607 might be formed in a manner similar to thatdescribed with reference to FIGS. 6B and 6C, including removal of theplug 598. And the channel material structure 610 might then be formed asdescribed with reference to FIG. 6C. Use of a high-K dielectric in theembodiments of FIGS. 10A and 10B might facilitate suppression ofelectron back-tunneling from the sense line 258. Although the examplesof FIGS. 10A-10B depict embodiments utilizing two discrete channels of apass gate 238, e.g., forming a separate semiconductor 589, suchstructures could also be used in embodiments utilizing a single channel.

Erasing memory cells in the unit column structures of embodiments mightproceed similar to a typical string of series-connected memory cells. Ina typical erase operation, an erase voltage level might be applied toboth ends of the string while the select gates and GG gates are operatedto induce GIDL current into the string. However, as one end of a unitcolumn structure is floating, inducing GIDL current from both ends isnot practicable. As such, in accordance with embodiments, an erasevoltage level might be applied to the upper data line 204, while the GGgates 220 and upper select gates 212 are operated to induce GIDL currentinto the unit column structures. For example, the GG gates 220 mightreceive a voltage level on control line 224, e.g., 11V less than theerase voltage level, while the upper select gates 212 might receive avoltage level on select line 215, e.g., 4V less than the erase voltagelevel. The access lines 202 might receive a nominal voltage levelconfigured to remove charge from the charge storage nodes, e.g., 0.5V.For some embodiments, the lower select gates 210 and the capacitances226 might receive a control gate voltage level configured to inhibiterasure, e.g., 4V less than the erase voltage level.

FIG. 11 is a timing diagram of a method of operating a memory inaccordance with an embodiment. For example, FIG. 11 might represent amethod of programming one or more memory cells, e.g., a logical page ofmemory cells. The method might be in the form of computer-readableinstructions, e.g., stored to the instruction registers 128. Suchcomputer-readable instructions might be executed by a controller, e.g.,the control logic 116, to cause the memory (e.g., relevant components ofthe memory) to perform the method.

The trace 1101 might depict voltage levels of an upper data line 204,e.g., a selected upper data line 204, selectively connected to a memorycell selected for programming during the programming operation, e.g., aselected memory cell to be enabled for programming. The trace 1103 mightdepict voltage levels of an upper data line 204, e.g., an unselectedupper data line 204, selectively connected to a memory cell not selectedfor programming during the programming operation, e.g., an unselectedmemory cell to be inhibited from programming. The trace 1105 mightdepict voltage levels of a select line 215. The trace 1107 might depictvoltage levels of an access line 202 connected to a selected memorycell, and the trace 1109 might depict voltage levels of an access line202 connected to an unselected memory cell.

At time to, in an optional seeding phase of the programming operation,traces 1101, e.g., selected upper data lines, and 1103, e.g., unselectedupper data lines, might be increased from an initial voltage level,e.g., a ground potential or 0V, to an inhibit voltage level, e.g., 2.3V.Trace 1105 might be increased from an initial voltage level, e.g., aground potential or 0V, to a voltage level sufficient to activate theupper select gates, e.g., 4V. Although not depicted, control line 224might also receive a voltage level sufficient to activate the GG gates.Trace 1107, e.g., the selected access line, and trace 1109, e.g.,unselected access lines, might be increased from an initial voltagelevel, e.g., a ground potential or 0V, to an intermediate voltage levelbetween a pass voltage level of the programming operation and theinitial voltage level. For example, traces 1107 and 1109 might beincreased to 4V.

At time t1, in an optional setup phase of the programming operation,trace 1101 might be returned to its initial voltage level. For someembodiments, trace 1101 might be decreased to some intermediate voltagelevel between the inhibit voltage level and its initial voltage level.The use of different voltages levels on upper data lines to be enabledfor programming might occur in programming schemes known as selectiveslow programming convergence (SSPC), where memory cells nearer to theirrespective intended data states are programmed more slowly (e.g.,partially enabled for programming) compared to memory cells farther fromtheir respective intended data states (e.g., fully enabled forprogramming) while receiving a same voltage level at their respectivecontrol gates. Different target data states might utilize differentintermediate voltage levels. Trace 1105 might be decreased to somevoltage level configured to activate upper select gates selectivelyconnected to selected upper data lines, and configured to deactivateupper select gates selectively connected to unselected upper data lines.Remaining traces 1103, 1107 and 1109 might remain at their presentvoltage levels.

At time t2, traces 1107 and 1109 might be increased to the pass voltagelevel of the programming operation. The pass voltage level is somevoltage level higher than the expected threshold voltage level of eachmemory cell connected to the selected and unselected access lines, e.g.,configured to activate each memory cell regardless of its data state.For example, traces 1107 and 1109 might be increased to 9V. At time t3,trace 1107 might be increased to a programming voltage level, e.g., 15Vor higher. The application of the programming voltage level from time t3to time t4 might be referred to as a programming pulse.

At time t4, the programming operation might be complete, and voltagelevels might be brought to respective recovery levels. For example,traces 1101 and 1103 might each be transitioned to 0.5V, and traces1105, 1107 and 1109 might each be transitioned to 4V. During theprogramming operation, control gate voltage levels to compensationgates, lower select gates and capacitances might remain at an initialvoltage level, e.g., a ground potential or 0V.

A verify operation might be performed after each programming pulse todetermine whether any memory cells have reached their respectiveintended data states, and/or their respective intermediate data statesin the case of SSPC programming. Any memory cells failing to reach theirrespective intended data states might be enabled for a subsequentprogramming pulse of a higher programming voltage level. In the case ofSSPC programming, memory cells not reaching their respectiveintermediate data states might be fully enabled for programming duringthe subsequent memory pulse, and memory cells reaching their respectiveintermediate data states, but not reaching their respective intendeddata states, might be partially enabled for programming during thesubsequent memory pulse.

FIG. 12 is a timing diagram of a method of operating a memory inaccordance with an embodiment. For example, FIG. 12 might represent amethod of sensing, e.g., reading or verifying, one or more memory cells,e.g., a logical page of memory cells. The method might be in the form ofcomputer-readable instructions, e.g., stored to the instructionregisters 128. Such computer-readable instructions might be executed bya controller, e.g., the control logic 116, to cause the memory (e.g.,relevant components of the memory) to perform the method. FIG. 12 willrefer specifically to elements of FIG. 2B, but it is to be understoodthat this description can be used with other memory array structuresdisclosed herein.

The trace 1211 might depict voltage levels of an upper data line 204,e.g., an upper data line 204 selectively connected to a memory cellselected for sensing during a sense operation, e.g., a selected memorycell. For example, the trace 1211 might correspond to upper data lines204 ₀-204 ₃. The trace 1213 might depict voltage levels of an accessline 202, e.g., a selected access line 202, connected to a selectedmemory cell, and the trace 1215 might depict voltage levels of an accessline 202, e.g., an unselected access line 202, not connected to aselected memory cell. For example, if the memory cells 208 selected forthe sense operation are connected to the access line 202 ₁, trace 1213might correspond to access line 202 ₁, and trace 1215 might correspondto access lines 202 ₀-202 _(N) other than access line 202 ₁. The trace1217 might depict voltage levels of a control line 213 connected tocompensation gates 211. The trace 1219 might depict voltage levels oflower select lines 214 connected to lower select gates 210. The trace1221 might depict voltage levels on control lines 228 connected tocapacitances 226.

The traces 1223 ₀ and 1223 ₁ might depict voltage levels of the channelsof the capacitances 226, e.g., a sense node, capacitively coupled to, orconnected to, a first control gate 240 of a pass gate 238 for a unitcolumn structure 256 whose selected memory cell is deactivated inresponse to a read voltage level, and for a unit column structure 256whose selected memory cell is activated in response to a read voltagelevel, respectively. The traces 1225 ₀ to 1225 ₃ might depict voltagelevels of backside gate lines 244, e.g., backside gate lines 244 ₀ to244 ₃ of the sub-block of memory cells 262 ₀ when the selected memorycells are contained in the unit column structures 256 ₀ to 256 ₃.

At time to, trace 1211 might be increased from an initial voltage level,e.g., a ground potential or 0V, to a precharge voltage level. Theprecharge voltage level might be some voltage level configured toactivate a first control gate 240 of a pass gate 238, e.g., for anenhancement type device, or deactivate a first control gate 240 of apass gate 238, e.g., for a depletion type device. For example, theprecharge voltage level might be 4V. The traces 1213 and 1215 might beincreased from an initial voltage level, e.g., a ground potential or 0V,to a pass voltage level of the sense operation. The pass voltage levelis some voltage level higher than the expected threshold voltage levelof each memory cell connected to the selected and unselected accesslines, e.g., configured to activate each memory cell regardless of itsdata state. For example, traces 1213 and 1215 might be increased to 9V.

At time t0, traces 1217, 1219 and 1221 might be increased from aninitial voltage level, e.g., a ground potential or 0V, to some voltagelevels configured to activate their corresponding compensation gates211, lower select gates 210, and capacitances 226, respectively.Although not depicted, upper select lines 215 and control line 224 mightalso receive voltage levels configured to activate their upper selectgates 212 and GG gates 220, respectively. Because these transistors aregenerally not programmed to the same threshold voltage levels as thememory cells, this voltage level might be lower, e.g., 2-3V.

With each transistor of a unit column structure 256 activated fromcapacitances 226 to GG gates 220, traces 1223 ₀ and 1223 ₁ mightincrease toward a voltage level of trace 1211 at time to. At time t0,the traces 1225 ₀ to 1225 ₃ might be increased to a voltage levelconfigured to activate a second select gate 242 of each correspondingpass gate 238. Although not depicted, voltage levels applied to thebackside gate lines 244 ₄ to 244 ₇, and the dummy backside gate line260, might also be configured to activate their corresponding pass gates238.

At time t1, the trace 1213 might be decreased to a read voltage levelfor the sense operation. The read voltage level might be some voltagelevel configured to distinguish between adjacent data states. As such,depending upon the data state programmed to memory cells receiving theread voltage at its control gate, that memory cells may or may notremain activated.

At time t2, trace 1211 might be decreased from the precharge voltagelevel to some lower voltage level. The lower voltage level might be somevoltage level configured to deactivate a first control gate 240 of apass gate 238, e.g., for an enhancement type device, or activate a firstcontrol gate 240 of a pass gate 238, e.g., for a depletion type device.For example, the lower voltage level might be its initial voltage level.If the selected memory cell of a unit column structure 256 isdeactivated at time t2, its sense node might be represented by the trace1223 ₀. If the selected memory cell of a unit column structure 256 isactivated at time t2, its sense node might be represented by the trace1223 ₁.

At time t3, trace 1219 might be decreased to some voltage levelconfigured to deactivate its corresponding lower select gates 210, e.g.,its initial voltage level. This might serve to isolate, e.g., trap, thecharge of its corresponding sense node from its corresponding upper dataline. At this time, the trace 1217 might be increased such that thecompensation gates 211 might absorb displacement charge from the lowerselect gates 210. Note that this discussion of trace 1217 might be mootfor embodiments not utilizing compensation gates 211.

With the sense nodes trapping charge configured to either activate ordeactivate the first control gates 240 of their respective pass gates238, selective activation of the second control gates 242 of theirrespective pass gates 238 can be used to determine whether theirrespective selected memory cells were activated or deactivated at timet2, such that the respective data states of those memory cells might bedetermined. In particular, the second control gates 242 for each of thepass gates 238 could be deactivated sequentially while the secondcontrol gates 242 for remaining pass gates 238 remain activated. Whilethe second control gate 242 for a particular pass gate 238 isdeactivated and the second control gates 242 for remaining pass gates238 are activated, an electrical connection of the lower data line 254to the source 216 might be dependent only upon whether the first controlgate 240 of the particular pass gate 238 is activated or not.

As such, at time t4, the trace 1225 ₀ might be transitioned to a voltagelevel configured to deactivate the second control gate 242 of itscorresponding pass gate 238 while traces 1225 ₁ to 1225 ₃ (and backsidegate lines 244 ₄ to 244 ₇ and dummy backside gate line 260) might bemaintained at a voltage level configured to activate the second controlgates 242 of their respective pass gates 238. The presence or absence ofan electrical path between the lower data line 254 and the common source216 might then be detected in manners well understood, such as sensing acurrent flow through, or a voltage change of, the lower data line 254.This in turn can indicate whether the corresponding selected memory cellwas activated or deactivated in response to the read voltage, which canthus indicate its data state in a manner similar to typical NAND memory.The trace 1225 ₀ might then be returned to a voltage level configured toactivate the second control gate 242 of is corresponding pass gate 238,and this process might be repeated for each remaining trace 1225 ₁ to1225 ₃.

For example, the trace 1225 ₁ might be transitioned to a voltage levelconfigured to deactivate the second control gate 242 of itscorresponding pass gate 238 at time t5, the trace 1225 ₂ might betransitioned to a voltage level configured to deactivate the secondcontrol gate 242 of its corresponding pass gate 238 at time t6, and thetrace 1225 ₃ might be transitioned to a voltage level configured todeactivate the second control gate 242 of its corresponding pass gate238 at time t7, while the remaining traces 1225 (and backside gate lines244 ₄ to 244 ₇ and dummy backside gate line 260) might be maintained ata voltage level configured to activate the second control gates 242 oftheir respective pass gates 238 at times when they are not transitionedlow.

FIG. 13 is a timing diagram of a method of operating a memory inaccordance with another embodiment. For example, FIG. 13 might representa method of sensing, e.g., reading or verifying, one or more memorycells, e.g., a logical page of memory cells. The method might be in theform of computer-readable instructions, e.g., stored to the instructionregisters 128. Such computer-readable instructions might be executed bya controller, e.g., the control logic 116, to cause the memory (e.g.,relevant components of the memory) to perform the method. FIG. 13 willrefer specifically to elements of FIG. 2B, but it is to be understoodthat this description can be used with other memory array structuresdisclosed herein.

The trace 1331 might depict voltage levels of an upper data line 204,e.g., an upper data line 204 selectively connected to a memory cellselected for sensing during a sense operation, e.g., a selected memorycell. For example, the trace 1331 might correspond to upper data lines204 ₀-204 ₃. The trace 1333 might depict voltage levels of an accessline 202, e.g., a selected access line 202, connected to a selectedmemory cell, and the trace 1335 might depict voltage levels of an accessline 202, e.g., an unselected access line 202, not connected to aselected memory cell. For example, if the memory cells 208 selected forthe sense operation are connected to the access line 202 ₁, trace 1333might correspond to access line 202 ₁, and trace 1335 might correspondto access lines 202 ₀-202 _(N) other than access line 202 ₁. The trace1337 might depict voltage levels of a control line 213 connected tocompensation gates 211. The trace 1339 might depict voltage levels oflower select lines 214 connected to lower select gates 210. The trace1341 might depict voltage levels on control lines 228 connected tocapacitances 226.

The traces 1343 ₀ and 1343 ₁ might depict voltage levels of the channelsof the capacitances 226, e.g., a sense node, capacitively coupled to, orconnected to, a first control gate 240 of a pass gate 238 for a unitcolumn structure 256 whose selected memory cell is deactivated inresponse to a read voltage level, and for a unit column structure 256whose selected memory cell is activated in response to a read voltagelevel, respectively. The traces 1345 ₀ to 1345 ₃ might depict voltagelevels of backside gate lines 244, e.g., backside gate lines 244 ₀ to244 ₃ of the sub-block of memory cells 262 ₀ when the selected memorycells are contained in the unit column structures 256 ₀ to 256 ₃.

At time to, trace 1331 might be increased from an initial voltage level,e.g., a ground potential or 0V to some voltage level that might beselected to mitigate drain induced barrier lowering (DIBL) and tomitigate read disturb. For example, the trace 1331 might be increased to1V. The traces 1343 ₀ and 1343 ₁ might increase due to the increase ofthe trace 1331. The traces 1333 and 1335 might be increased from aninitial voltage level, e.g., 1V, to a pass voltage level of the senseoperation. The pass voltage level is some voltage level higher than theexpected threshold voltage level of each memory cell connected to theselected and unselected access lines, e.g., configured to activate eachmemory cell regardless of its data state. For example, traces 1333 and1335 might be increased to 9V.

At time to, traces 1337, 1339 and 1341 might be increased from aninitial voltage level, e.g., a ground potential or 0V, to some voltagelevels configured to activate their corresponding compensation gates211, lower select gates 210, and capacitances 226, respectively.Although not depicted, upper select lines 215 and control line 224 mightalso receive voltage levels configured to activate their upper selectgates 212 and GG gates 220, respectively. Because these transistors aregenerally not programmed to the same threshold voltage levels as thememory cells, this voltage level might be lower, e.g., 2-3V.

At time t1, the trace 1339 might be decreased to some voltage levelconfigured to deactivate its corresponding lower select gates 210, e.g.,its initial voltage level. This might serve to isolate the capacitances226 from their corresponding upper data line 204. At this time, thetrace 1337 might be increased. Note that this discussion of trace 1337might be moot for embodiments not utilizing compensation gates 211.

At time t2, the control lines 228 might be biased to boost the channelsof the capacitances 226 such the traces 1343 ₀ and 1343 ₁ might furtherincrease. The increase in voltage level of trace 1341 might besufficient to boost the traces 1343 ₀ and 1343 ₁ to some prechargevoltage level configured to activate a first control gate 240 of a passgate 238, e.g., for an enhancement type device, or deactivate a firstcontrol gate 240 of a pass gate 238, e.g., for a depletion type device.For example, the precharge voltage level might be 4V.

At time t4, the trace 1333 might be decreased to a read voltage levelfor the sense operation. The read voltage level might be some voltagelevel configured to distinguish between adjacent data states. As such,depending upon the data state programmed to memory cells receiving theread voltage at its control gate, that memory cells may or may notremain activated.

At time t5, the trace 1339 might be increased to a voltage levelsufficient to activate the corresponding lower select gates 210. Thevoltage level of trace 1339 between times t5 and t6 might be selected tolimit a voltage level of the channel of a selected memory cell to avalue near the voltage level of the trace 1331 at time t5. If theselected memory cell of a unit column structure 256 is deactivated attime t5, its sense node might be represented by the trace 1343 ₀. If theselected memory cell of a unit column structure 256 is activated at timet5, its sense node might be represented by the trace 1343 ₁.

At time t6, the trace 1331 might be decreased to some lower voltagelevel. The lower voltage level might be some voltage level configured todeactivate a first control gate 240 of a pass gate 238, e.g., for anenhancement type device, or activate a first control gate 240 of a passgate 238, e.g., for a depletion type device. For example, the lowervoltage level might be its initial voltage level. This might result in afurther decrease in the voltage level of the trace 1343 ₁.

At time t7, the trace 1339 might be decreased to some voltage levelconfigured to deactivate its corresponding lower select gates 210, e.g.,its initial voltage level. This might serve to isolate, e.g., trap, thecharge of its corresponding sense node from its corresponding upper dataline.

With the sense nodes trapping charge configured to either activate ordeactivate the first control gates 240 of their respective pass gates238, selective activation of the second control gates 242 of theirrespective pass gates 238 can be used to determine whether theirrespective selected memory cells were activated or deactivated at timet6, such that the respective data states of those memory cells might bedetermined.

As such, at time t8, the trace 1345 ₀ might be transitioned to a voltagelevel configured to deactivate the second control gate 242 of itscorresponding pass gate 238 while traces 1345 ₁ to 1345 ₃ (and backsidegate lines 244 ₄ to 244 ₇ and dummy backside gate line 260) might bemaintained at a voltage level configured to activate the second controlgates 242 of their respective pass gates 238. The presence or absence ofan electrical path between the lower data line 254 and the common source216 might then be detected in manners well understood, such as sensing acurrent flow through, or a voltage change of, the lower data line 254.This in turn can indicate whether the corresponding selected memory cellwas activated or deactivated in response to the read voltage, which canthus indicate its data state in a manner similar to typical NAND memory.The trace 1345 ₀ might then be returned to a voltage level configured toactivate the second control gate 242 of is corresponding pass gate 238,and this process might be repeated for each remaining trace 1345 ₁ to1345 ₃.

For example, the trace 1345 ₁ might be transitioned to a voltage levelconfigured to deactivate the second control gate 242 of itscorresponding pass gate 238 at time t9, the trace 1345 ₂ might betransitioned to a voltage level configured to deactivate the secondcontrol gate 242 of its corresponding pass gate 238 at time t10, and thetrace 1345 ₃ might be transitioned to a voltage level configured todeactivate the second control gate 242 of its corresponding pass gate238 at time t11, while the remaining traces 1345 (and backside gatelines 244 ₄ to 244 ₇ and dummy backside gate line 260) might bemaintained at a voltage level configured to activate the second controlgates 242 of their respective pass gates 238 at times when they are nottransitioned low.

FIG. 14 is a timing diagram of a method of operating a memory inaccordance with a further embodiment. For example, FIG. 14 mightrepresent a method of sensing, e.g., reading or verifying, one or morememory cells, e.g., a logical page of memory cells. The method might bein the form of computer-readable instructions, e.g., stored to theinstruction registers 128. Such computer-readable instructions might beexecuted by a controller, e.g., the control logic 116, to cause thememory (e.g., relevant components of the memory) to perform the method.FIG. 14 will refer specifically to elements of FIG. 2B, but it is to beunderstood that this description can be used with other memory arraystructures disclosed herein.

The trace 1451 might depict voltage levels of an upper data line 204,e.g., an upper data line 204 selectively connected to a memory cellselected for sensing during a sense operation, e.g., a selected memorycell. For example, the trace 1451 might correspond to upper data lines204 ₀-204 ₃. The trace 1453 might depict voltage levels of an accessline 202, e.g., a selected access line 202, connected to a selectedmemory cell, and the trace 1455 might depict voltage levels of an accessline 202, e.g., an unselected access line 202, not connected to aselected memory cell. For example, if the memory cells 208 selected forthe sense operation are connected to the access line 202 ₁, trace 1453might correspond to access line 202 ₁, and trace 1455 might correspondto access lines 202 ₀-202 _(N) other than access line 202 ₁. The trace1459 might depict voltage levels of lower select lines 214 connected tolower select gates 210. The trace 1461 might depict voltage levels oncontrol lines 228 connected to capacitances 226.

The traces 1463 ₀ and 1463 ₁ might depict voltage levels of the channelsof the capacitances 226, e.g., a sense node, capacitively coupled to, orconnected to, a first control gate 240 of a pass gate 238 for a unitcolumn structure 256 whose selected memory cell is deactivated inresponse to a read voltage level, and for a unit column structure 256whose selected memory cell is activated in response to a read voltagelevel, respectively. The traces 1465 ₀ to 1465 ₃ might depict voltagelevels of backside gate lines 244, e.g., backside gate lines 244 ₀ to244 ₃ of the sub-block of memory cells 262 ₀ when the selected memorycells are contained in the unit column structures 256 ₀ to 256 ₃.

At time to, trace 1451 might be increased from an initial voltage level,e.g., a ground potential or 0V, to a precharge voltage level. Theprecharge voltage level might be some voltage level configured toactivate a first control gate 240 of a pass gate 238, e.g., for anenhancement type device, or deactivate a first control gate 240 of apass gate 238, e.g., for a depletion type device. For example, theprecharge voltage level might be 4V. The traces 1453 and 1455 might beincreased from an initial voltage level, e.g., a ground potential or 0V,to a pass voltage level of the sense operation. The pass voltage levelis some voltage level higher than the expected threshold voltage levelof each memory cell connected to the selected and unselected accesslines, e.g., configured to activate each memory cell regardless of itsdata state. For example, traces 1453 and 1455 might be increased to 9V.

At time t0, traces 1459 and 1461 might be increased from an initialvoltage level, e.g., a ground potential or 0V, to some voltage levelsconfigured to activate their corresponding lower select gates 210 andcapacitances 226, respectively. Although not depicted, upper selectlines 215 and control line 224 might also receive voltage levelsconfigured to activate their upper select gates 212 and GG gates 220,respectively. Because these transistors are generally not programmed tothe same threshold voltage levels as the memory cells, this voltagelevel might be lower, e.g., 2-3V.

With each transistor of a unit column structure 256 activated fromcapacitances 226 to GG gates 220, traces 1463 ₀ and 1463 ₁ mightincrease toward a voltage level of trace 1451 at time t0. At time t0,the traces 1465 ₀ to 1465 ₃ might be increased to a voltage levelconfigured to activate a second select gate 242 of each correspondingpass gate 238. Although not depicted, voltage levels applied to thebackside gate lines 244 ₄ to 244 ₇, and the dummy backside gate line260, might also be configured to activate their corresponding pass gates238.

At time t1, the trace 1453 might be decreased to a read voltage levelfor the sense operation. The read voltage level might be some voltagelevel configured to distinguish between adjacent data states. As such,depending upon the data state programmed to memory cells receiving theread voltage at its control gate, that memory cells may or may notremain activated.

At time t2, trace 1451 might be decreased from the precharge voltagelevel to some lower voltage level. The lower voltage level might be somevoltage level configured to deactivate a first control gate 240 of apass gate 238, e.g., for an enhancement type device, or activate a firstcontrol gate 240 of a pass gate 238, e.g., for a depletion type device.For example, the lower voltage level might be its initial voltage level.If the selected memory cell of a unit column structure 256 isdeactivated at time t2, its sense node might be represented by the trace1463 ₀. If the selected memory cell of a unit column structure 256 isactivated at time t2, its sense node might be represented by the trace1463 ₁.

At time t3, trace 1459 might be decreased to some voltage levelconfigured to deactivate its corresponding lower select gates 210, e.g.,its initial voltage level. This might serve to isolate, e.g., trap, thecharge of its corresponding sense node from its corresponding upper dataline. With the sense nodes isolated from their corresponding upper datalines, the traces 1453 and 1455 optionally might be discharged at timet4, e.g., to their initial voltage levels/

With the sense nodes trapping charge configured to either activate ordeactivate the first control gates 240 of their respective pass gates238, selective activation of the second control gates 242 of theirrespective pass gates 238 can be used to determine whether theirrespective selected memory cells were activated or deactivated at timet2, such that the respective data states of those memory cells might bedetermined.

As such, at time t4, the trace 1465 ₀ might be transitioned to a voltagelevel configured to deactivate the second control gate 242 of itscorresponding pass gate 238 while traces 1465 ₁ to 1465 ₃ (and backsidegate lines 244 ₄ to 244 ₇ and dummy backside gate line 260) might bemaintained at a voltage level configured to activate the second controlgates 242 of their respective pass gates 238. The presence or absence ofan electrical path between the lower data line 254 and the common source216 might then be detected in manners well understood, such as sensing acurrent flow through, or a voltage change of, the lower data line 254.This in turn can indicate whether the corresponding selected memory cellwas activated or deactivated in response to the read voltage, which canthus indicate its data state in a manner similar to typical NAND memory.The trace 1465 ₀ might then be returned to a voltage level configured toactivate the second control gate 242 of is corresponding pass gate 238,and this process might be repeated for each remaining trace 1465 ₁ to1465 ₃.

For example, the trace 1465 ₁ might be transitioned to a voltage levelconfigured to deactivate the second control gate 242 of itscorresponding pass gate 238 at time t5, the trace 1465 ₂ might betransitioned to a voltage level configured to deactivate the secondcontrol gate 242 of its corresponding pass gate 238 at time t6, and thetrace 1465 ₃ might be transitioned to a voltage level configured todeactivate the second control gate 242 of its corresponding pass gate238 at time t7, while the remaining traces 1465 (and backside gate lines244 ₄ to 244 ₇ and dummy backside gate line 260) might be maintained ata voltage level configured to activate the second control gates 242 oftheir respective pass gates 238 at times when they are not transitionedlow.

CONCLUSION

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement that is calculated to achieve the same purposemight be substituted for the specific embodiments shown. Manyadaptations of the embodiments will be apparent to those of ordinaryskill in the art. Accordingly, this application is intended to cover anyadaptations or variations of the embodiments.

What is claimed is:
 1. An array of memory cells, comprising: a dataline; a source; a plurality of pass gates connected in series betweenthe data line and the source, wherein each pass gate of the plurality ofpass gates comprises a first channel, a second channel, a first controlgate capacitively coupled to its first channel, a second control gatecapacitively coupled to its second channel, a first source/drain regionconnected to its first channel and to its second channel, and a secondsource/drain region connected to its first channel and to its secondchannel; a plurality of unit column structures, wherein each unit columnstructure of the plurality of unit column structures comprises arespective plurality of series-connected non-volatile memory cellsconnected in series with a respective plurality of series-connectedfield-effect transistors, wherein a channel of each non-volatile memorycell of the plurality of series-connected non-volatile memory cells anda channel of each field-effect transistor of the plurality ofseries-connected field-effect transistors are selectively connected toone another; and a plurality of backside gate lines, wherein eachbackside gate line is connected to the second control gate of arespective pass gate of the plurality of pass gates; wherein, for eachunit column structure of the plurality of unit column structures, thechannel of a particular field-effect transistor of its respectiveplurality of field-effect transistors is capacitively coupled to thefirst channel of a respective pass gate of the plurality of pass gates.2. The array of memory cells of claim 1, wherein, for each unit columnstructure of the plurality of unit column structures, a material formingthe channel of the particular field-effect transistor of its respectiveplurality of field-effect transistors is electrically connected to thefirst control gate of its respective pass gate.
 3. The array of memorycells of claim 1, wherein, for each unit column structure of theplurality of unit column structures, a material forming the channel ofthe particular field-effect transistor of its respective plurality offield-effect transistors is capacitively coupled to the first controlgate of its respective pass gate.
 4. The array of memory cells of claim3, further comprising a high-K dielectric between the material formingthe channel of the particular field-effect transistor of the respectiveplurality of field-effect transistors of a particular unit columnstructure and the first channel of the respective pass gate of theparticular unit column structure, wherein the high-K dielectric isformed below the material forming the channel of the particularfield-effect transistor of the respective plurality of field-effecttransistors of the particular unit column structure.
 5. The array ofmemory cells of claim 4, wherein the high-K dielectric is further formedadjacent sidewalls of the material forming the channel of the particularfield-effect transistor of the respective plurality of field-effecttransistors of a particular unit column structure.
 6. The array ofmemory cells of claim 1, wherein the first control gate of a particularpass gate of the plurality of pass gates is permanently electricallyfloating.
 7. The array of memory cells of claim 1, wherein the firstsource/drain region and the second source/drain region of a particularpass gate of the plurality of pass gates each comprise a respectiveconductively-doped portion of an instance of a semiconductor.
 8. Thearray of memory cells of claim 7, wherein the instance of thesemiconductor has a serpentine shape.
 9. The array of memory cells ofclaim 7, wherein the first channel of the particular pass gate and thesecond channel of the particular pass gate are a same channel of theparticular pass gate.
 10. The array of memory cells of claim 7, whereinthe instance of the semiconductor contains the second channel of theparticular pass gate.
 11. The array of memory cells of claim 7, whereinthe instance of the semiconductor is a first instance of thesemiconductor, and wherein the first source/drain region and the secondsource/drain region of the particular pass gate each further comprise arespective conductively-doped portion of a second instance of asemiconductor.
 12. The array of memory cells of claim 11, wherein thefirst instance of the semiconductor contains the second channel of theparticular pass gate, and wherein the second instance of thesemiconductor contains the first channel of the particular pass gate.13. The array of memory cells of claim 1, wherein the first channel of aparticular pass gate of the plurality of pass gates comprises a firstsemiconductor, wherein the second channel of the particular pass gatecomprises a second semiconductor, wherein the first source/drain regionof the particular pass gate comprises a first instance ofconductively-doped semiconductor formed between the first semiconductorand the second semiconductor, and wherein the second source/drain regionthe particular pass gate comprises a second instance of theconductively-doped semiconductor formed between the first semiconductorand the second semiconductor.
 14. An array of memory cells, comprising:a data line; a source; a plurality of pass gates connected in seriesbetween the data line and the source, wherein each pass gate of theplurality of pass gates comprises a first channel, a second channel, afirst control gate capacitively coupled to its first channel, a secondcontrol gate capacitively coupled to its second channel, a firstsource/drain region connected to its first channel and to its secondchannel, and a second source/drain region connected to its first channeland to its second channel; a plurality of unit column structures,wherein each unit column structure of the plurality of unit columnstructures comprises a respective plurality of series-connectednon-volatile memory cells connected in series with a respectiveplurality of series-connected field-effect transistors, wherein achannel of each non-volatile memory cell of the plurality ofseries-connected non-volatile memory cells and a channel of eachfield-effect transistor of the plurality of series-connectedfield-effect transistors are selectively connected to one another; and aplurality of backside gate lines, wherein each backside gate line isconnected to the second control gate of a respective pass gate of theplurality of pass gates; wherein, for each unit column structure of theplurality of unit column structures, the channel of a particularfield-effect transistor of its respective plurality of field-effecttransistors is capacitively coupled to a conductive element of the firstcontrol gate of a respective pass gate of the plurality of pass gates.15. The array of memory cells of claim 14, wherein the conductiveelement of the first control gate of the respective pass gate for aparticular unit column structure of the plurality of unit columnstructures is formed below a material forming the channel of theparticular field-effect transistor of the respective plurality offield-effect transistors of the particular unit column structure. 16.The array of memory cells of claim 15, wherein the conductive element ofthe first control gate of the respective pass gate for a particular unitcolumn structure of the plurality of unit column structures is furtherformed adjacent sidewalls of the material forming the channel of theparticular field-effect transistor of the respective plurality offield-effect transistors of the particular unit column structure. 17.The array of memory cells of claim 14, wherein the conductive element ofthe first control gate of the respective pass gate for a particular unitcolumn structure of the plurality of unit column structures comprises aconductively-doped polysilicon.
 18. An array of memory cells,comprising: a data line; a source; a plurality of pass gates connectedin series between the data line and the source, wherein each pass gateof the plurality of pass gates comprises a first channel, a secondchannel, a first control gate capacitively coupled to its first channel,a second control gate capacitively coupled to its second channel, afirst source/drain region connected to its first channel and to itssecond channel, and a second source/drain region connected to its firstchannel and to its second channel; a plurality of unit columnstructures, wherein each unit column structure of the plurality of unitcolumn structures comprises a respective plurality of series-connectednon-volatile memory cells connected in series with a respectiveplurality of series-connected field-effect transistors, wherein achannel of each non-volatile memory cell of the plurality ofseries-connected non-volatile memory cells and a channel of eachfield-effect transistor of the plurality of series-connectedfield-effect transistors are selectively connected to one another; and aplurality of backside gate lines, wherein each backside gate line isconnected to the second control gate of a respective pass gate of theplurality of pass gates; wherein, for each unit column structure of theplurality of unit column structures, a material forming the channel of aparticular field-effect transistor of its respective plurality offield-effect transistors is electrically connected to a conductiveelement of the first control gate of a respective pass gate of theplurality of pass gates.
 19. The array of memory cells of claim 18,wherein, for each unit column structure of the plurality of unit columnstructures, the conductive element of the first control gate of therespective pass gate for that unit column structure is formed below thematerial forming the channel of the particular field-effect transistorof the respective plurality of field-effect transistors of that unitcolumn structure.
 20. The array of memory cells of claim 19, wherein,for each unit column structure of the plurality of unit columnstructures, the conductive element of the first control gate of therespective pass gate for that unit column structure is further formedadjacent sidewalls of the material forming the channel of the particularfield-effect transistor of the respective plurality of field-effecttransistors of that unit column structure.
 21. The array of memory cellsof claim 18, wherein, for each unit column structure of the plurality ofunit column structures, the conductive element of the first control gateof the respective pass gate for that unit column structure comprises afirst conductively-doped polysilicon, and a second conductively-dopedpolysilicon formed between the first conductively-doped polysilicon andthe material forming the channel of the particular field-effecttransistor of the respective plurality of field-effect transistors ofthat unit column structure.